Centre for Pesticide Suicide Prevention — General Support (January 2021)

Note: This page summarizes the rationale behind a GiveWell Incubation Grant to the Centre for Pesticide Suicide Prevention. CPSP staff reviewed this page prior to publication.

Published: April 2021

We spoke with CPSP about updates on its work on May 19, 2021.

The organization

CPSP was founded in 2017 with $1.3 million in seed funding from Open Philanthropy on the basis of GiveWell's recommendation. CPSP's director is Professor Michael Eddleston, a professor of clinical toxicology at the University of Edinburgh whose research focuses on self-harm through poisoning.1

The grant

Activities

The grant is intended to fully fund CPSP's operations over the next three years. This includes maintaining CPSP's activities in Nepal and India, and expanding activities to China. CPSP also plans to work with regional regulatory bodies and multilateral organizations to assist other countries to reduce pesticide suicide.2

CPSP's activities vary by country but are structured around:

1. Collecting data on which pesticides are commonly used in suicide
2. Supporting regulators and agriculture ministries to identify effective alternatives to those pesticides
3. Supporting governments in regulating dangerous pesticides used in suicide
4. Setting up systems that will allow monitoring of the effect of the bans on suicides and agriculture
5. Providing clinical guidance on the best medical management of pesticide poisoned patients3

CPSP's projected budget is available here.

Case for the grant

We recommended this grant because:

1. Pesticide suicide is a focus area for GiveWell based on our assessment of the evidence for deregistration of highly hazardous pesticides (HHPs) reducing suicide rates, its large burden of disease, and its relative neglectedness by other philanthropic funders. (more)
2. Strong track record. CPSP's work over the previous grant period contributed to bans on the two pesticides most commonly used in deaths by suicide in Nepal. CPSP also worked in India over the previous grant period, where it had less impact. A back-of-the-envelope calculation suggests that CPSP's work was significantly more cost-effective than cash transfers to people living in extreme poverty. That estimate relies on a number of uncertain assumptions, such as the number of years regulation was accelerated by, which make it difficult to directly compare with direct delivery opportunities. (more)
3. We believe CPSP's director, Professor Michael Eddleston, is a strong fit to lead this work. Professor Eddleston is one of the most prominent academics working on pesticide suicide and appears to be well-respected by relevant decision-makers.

Case against the grant

1. Effect on agricultural productivity. We believe the effect of banning pesticides on agricultural productivity is small enough that it is outweighed by the benefits of suicide prevention. However, we remain uncertain about the precise impact individual pesticide bans may have on agricultural productivity. (more)
2. Unpredictability of policy change. CPSP's work involves expanding to China, and devoting substantial resources to work with multilateral and regional pesticide regulatory bodies. We believe this work is promising, based primarily on CPSP's track record, but its success depends on a number of factors that are difficult to quantify. (more)
3. Uncertain evidence base. The evidence base behind the effect of pesticide regulation is less certain than the evidence base for our top charities, although we find it compelling. (more)

Cost-effectiveness

We completed a back-of-the-envelope calculation on CPSP's future cost-effectiveness to weigh the considerations above. That rough estimate suggested CPSP's work over the next grant period would be in the range of 50x as cost-effective as GiveDirectly’s program in expectation. We completed this back-of-the-envelope calculation to discipline ourselves to make our assumptions explicit and quantitatively weigh different considerations. However, the estimate relies on a number of difficult best-guess assumptions and judgment calls about modelling structure. It therefore contains less information-value than cost-effectiveness estimates for our top charities, which limits its comparability. (In general, there are limitations to all of our cost-effectiveness analyses, and we believe they should not be taken literally, due to the significant uncertainty around them.)

Our estimates of a given program's cost-effectiveness tend to go down as we gain more information; however, we believe this grant to CPSP is likely to be above the range of cost-effectiveness of our top charities even if our current estimate is significantly off.

Our back-of-the-envelope estimate is available here. We outline some of the more important inputs below.

Forecasts of chance of success

We estimate that CPSP has a 60% chance of affecting policy in Sri Lanka and Nepal over the grant period, a 50% chance of affecting policy in Maharashtra state in India, and a 30% chance of affecting policy in China. More granular forecasts for different levels of impact are available in this spreadsheet.

These forecasts are highly uncertain. Factors we took into account included:

• Track record. CPSP has a track record of assisting with regulation in Nepal (discussed below). CPSP's director, Professor Eddleston, has a track record of assisting regulators in Sri Lanka.4 CPSP's work has not yet led to additional pesticide regulation in India, and CPSP has not yet begun work in China.
• Industry opposition. Our understanding is that industry opposition to pesticide bans is likely to be more powerful in India and China, which are major pesticide exporters.5
• Relationships with key decision-makers. Correspondence between CPSP and a regulator in China (where CPSP is expanding its work) suggests that there is demand for CPSP's assistance from decision-makers.6 We have not seen a formal memorandum of understanding with China.
• Foreign NGO restrictions. Foreign NGOs in China and India are subject to a number of restrictions.7 These restrictions slowed CPSP's early work in India.8 We are unsure of the extent to which they will affect CPSP's work in China.

We also expect that CPSP will be able to effect change in countries covering about a quarter of the remaining burden of suicide (excluding countries CPSP is directly working with) through the combination of its work with UN agencies and regional regulatory bodies. This estimate seems reasonable to us based on CPSP's plans, but is necessarily speculative.

Number of years brought forward

Our best guess is that policy changes CPSP contributes to will be accelerated by nine years, and so we model nine years of benefit. This assumption is very uncertain, and makes it difficult to compare the cost-effectiveness of this grant with that of GiveWell's top charities.

We selected ten years as a reasonable default for evaluating policy change in general, and then adjusted down to nine years because there appears to be some global momentum toward regulating HHPs.9 We only applied a small downward adjustment because we expect that the specific pesticides used in suicide are less likely to be banned without the data that CPSP is planning to collect.

Baseline burden of pesticide suicide

We use estimates from Mew et al. 2017, a systematic review of the burden of pesticide suicide in different countries. We adjust these estimates downwards to account for a likely decline in pesticide suicide since the studies in the review were conducted. We apply more aggressive downward adjustments in countries where we are aware that pesticides have been recently banned. See discussion of some of the limitations of Mew et al. 2017 below.

Effectiveness of pesticide bans

We estimate that banning a pesticide will reduce the burden of suicide by about 80% of the number of suicides using that pesticide. This estimate is based on analysis of the relative case fatalities of banned pesticides and their potential substitutes in Sri Lanka (more). We model this estimate as ranging between 70% and 90% depending on the proportion of pesticides used in suicide that are banned.10

Other considerations

We include adjustments for other considerations that might affect the cost-effectiveness of the grant but that we have investigated in less depth, or feel less certain about. These include:

Positive considerations:

• Reduced treatment costs due to pesticide poisoning
• Reduced morbidity due to pesticide poisoning
• Reduced accidental poisoning due to pesticide poisoning
• Reduced consumer exposure to pesticide residues from HHPs
• Reduced ecological harm from HHPs

Negative considerations:

• Chance that the ban is not successfully enforced
• Government cost of enforcing regulation
• Potential risk of reducing agricultural productivity
• Additional monitoring costs that CPSP might incur in the future but that are not directly related to achieving additional policy change
• The extent to which pesticide suicide will decline without intervention

The cause

Pesticide suicide is one of the promising areas we identified as part of GiveWell's work investigating giving opportunities to assist governments in low- and middle-income countries (LMICs) in the design and implementation of effective public health regulations.11

Regulation of pesticides to reduce suicide is one of GiveWell's focus areas because:

• Pesticide suicide imposes a substantial burden of disease. The most recent credible estimates we have seen suggest that 110,000-168,000 people die by deliberate ingestion of pesticides each year. (more)
• Pesticide suicide is neglected relative to its burden. To our knowledge, there are no other philanthropic funders supporting policy work to reduce suicide from pesticides. (more)
• Based on a review of relevant evidence, we believe there is a compelling case that pesticide regulation can meaningfully reduce the burden of both pesticide suicide and overall suicide. (more)
• CPSP is an organization that has made progress in assisting governments to identify and deregister the pesticides that would have the greatest impact on reducing the suicide rate. (more)

The main case against is that:

• The evidence on whether banning particular pesticides may reduce agricultural productivity is inconclusive. Based on the evidence that does exist, we expect the effect on agriculture is likely to be small and outweighed by the positive case for preventing suicides. (more)
• The evidence base behind the effect of pesticide regulation is more uncertain than the evidence base for our top charities, although we find it compelling. (more)

Details follow.

The problem

Suicide through pesticide poisoning is a form of self-harm involving deliberate ingestion of toxic pesticides.

The World Health Organization (WHO) estimates that 800,000 people die by suicide each year.12

Mew et al. 2017 (the most recent systematic review we have found) suggests that 14-20% (110,000-168,000) of those suicides between 2010 and 2014 were a result of deliberate ingestion of pesticides.13 Data was unavailable in countries covering ~30% of the global population. Estimates of pesticide suicide rates for those countries were based on regional averages.14 Estimates are particularly uncertain for Africa, where data was available for only 6% of the population.15 We have not vetted the individual studies in this review.

The Million Death Study, a nationally representative survey of causes of death in India,16 suggests that between 2001 and 2003, 40% of male suicides and 56% of female suicides occurred between the ages of 15 and 29 years.17 A WHO report claims that pesticide suicide is particularly prevalent in rural populations, where agricultural workers have easy access to pesticides.18

Other organizations and funders

CPSP is the only organization focused on providing technical assistance to reduce deaths from pesticide suicide in Nepal,19 and the only organization we know of doing this work globally. A number of other organizations work on mitigating the harms of pesticide more generally, but appear to be more focused on other potential harms from pesticides than suicide specifically.20

We are also not aware of any other major funders supporting this work. To our knowledge, funding recommended by GiveWell is the only substantial funding CPSP has received.

What is the intervention?

The intervention involves identifying and deregistering the pesticides that are (a) commonly used in suicide and (b) have a high case fatality when deliberately ingested.21 We expect deregistering pesticides with a high case fatality would reduce the suicide rate by causing people to switch methods to other, less lethal pesticides, reducing the proportion of suicide attempts that result in death (more).

How strong is the evidence for the intervention?

Overall, we find the evidence that pesticide deregistration can reduce overall suicide rates compelling. There is direct evidence that bans on particular pesticides were followed by reductions in national suicide rates. This direct evidence has important limitations that make it less strong than the evidence for most of our top charities: it is observational and relies on data of uncertain quality. However, when taken in conjunction with mechanistic evidence supporting the theory of change, we believe the simplest explanation is that the declines in suicide rates were partially caused by the preceding pesticide bans.

We expect the impact of a pesticide ban in a particular context to depend on (i) the number of suicide attempts using the banned pesticide, (ii) the proportion of suicide attempts that result in death from the banned pesticide, and (iii) the proportion of suicide attempts that result in death from the method that people substitute.

Details follow.

Direct evidence

The direct evidence that targeted bans of pesticides result in reductions in suicide rates suggests potentially high effect sizes, but is limited to observational studies that compare suicide rates before pesticide bans with suicide rates in the years following bans.

Gunnell et al. 2017 is a systematic review of observational studies investigating the effect on suicide rates of restricting availability of pesticides. It identifies 12 studies on the effect of targeted bans of pesticides on pesticide suicide rates or overall suicide rates in six countries.22 The review reports that suicide rates declined, sometimes substantially, in the years following bans in five of the six countries.23 The review does not include a meta-analysis due to the heterogeneity of the interventions studied.24

We vetted the two studies in the review evaluating the effect of pesticide bans in Sri Lanka. We focused on Sri Lanka because (i) Professor Eddleston, CPSP's director, contributed to the decision to ban certain pesticides in Sri Lanka,25 and so we believed this evidence was most relevant to the impact of future work, and (ii) there is evidence from Sri Lanka on which pesticides were most commonly used in suicide over this period, which allows for a richer understanding of what caused the decline in the suicide rate.26

• Gunnell et al. 2007 finds a 50% decline in the suicide rate between 1995 and 2005.27 The decline followed bans on pesticides commonly used in suicide (methamidophos and monocrotophos in 1995, endosulfan in 1998).28
• Knipe et al. 2017 finds a 21% decline in the suicide rate between 2011 and 2015.29 The decline followed phased bans of pesticides commonly used in suicide (paraquat, dimethoate, and fenthion) between 2008 and 2011.30

We note three major limitations of these studies, which limit causal inference:

• They use time series data, with no comparison group. It is possible that the decline in pesticide suicides was caused by events other than the pesticide ban.31
• They use national-level suicide data of uncertain quality.32
• There were a number of pesticide bans in Sri Lanka between 1984 and 2011, not all of which were followed by declines in the suicide rate.33

However, we believe it is likely that pesticide bans were at least partially responsible for the decline in suicides.

• The decline in the suicide rate following pesticide bans in both studies was large and driven by a decline in suicide by self-poisoning.34
• Dawson et al. 2010 and van der Hoek and Konradsen 2006, two analyses of Sri Lankan hospital records for poisoning patients, indicate that (i) the banned pesticides were among the most commonly used in death by suicide, and (ii) self-poisoning with the banned pesticides was more likely to result in death than self-poisoning with other pesticides.35

Mechanistic evidence

An alternative approach to assessing the effect of pesticide bans is to assess the evidence on each step of the causal pathway. The hypothesized causal pathway is:

1. People attempting suicide with the banned pesticide will no longer use that pesticide in their suicide attempt.
2. Most of these people will attempt suicide using a different pesticide. Some proportion may also switch to other methods.
3. The case fatality of other pesticides is lower than for the banned pesticide, meaning the rate of deaths by suicide would decline on net.
4. Most people who survive a suicide attempt do not later die by suicide.

If a ban is well enforced, when stocks of the pesticide are depleted, people will no longer use that pesticide in suicide (step 1). We address each of the other steps below. Taken together with the direct evidence, we find this mechanistic evidence compelling.

(2) Most of these people will attempt suicide using a different pesticide. Some proportion may also switch to other methods.

We expect that the majority of people who attempt suicide with a particular pesticide would substitute a different pesticide if that pesticide was unavailable.

Eddleston et al. 2006 conducted interviews with 268 self-poisoning patients in rural Sri Lanka, 65 of whom were pesticide poisoning patients.36 Patients were asked the reason for their choice of poison. 54 of those patients (83%) responded that they chose that pesticide either because of its easy availability, or because it was the only poison available. Four patients (6%) responded that they chose that poison because of its lethality.37 Furthermore, 71-75% of pesticide poisoning patients obtained the poison from their home, with only 17-20% buying the pesticide from a shop specifically for the attempt.38

This study has some limitations. The sample was biased toward less severe poisoning patients,39 and we are unsure how it would generalize to different contexts. But we believe it constitutes evidence that people who attempt suicide by pesticide generally choose the pesticide based on availability rather than characteristics of that particular pesticide, implying that restricting access to one pesticide would likely lead them to substitute a different pesticide.

In our cost-effectiveness analysis, we assume that, if a ban on a pesticide is successfully enforced, everyone who would have attempted suicide with that pesticide instead attempts suicide with a different pesticide.

We have not prioritized deeper review of other evidence relevant to this question because, if some people did not substitute a different pesticide, it would increase rather than decrease our estimate of the effectiveness of pesticide regulation to reduce suicide.

It is plausible that some proportion of people substitute non-pesticide methods of suicide. But we believe this is unlikely to be a significant proportion of cases because the intervention is primarily targeted at regulating particular pesticides, rather than decreasing overall pesticide availability.40

3) The case fatality of those other methods is lower than for the banned pesticide, meaning the rate of deaths by suicide would decline on net.

Moebus and Boedeker 2017 (preprint) is a preprint of a systematic review that identified 67 studies on the case fatality of 68 different pesticides.41 It concludes that, of 67 pesticides (categorized by active ingredient) for which data is available, 19 had a median (of study point estimates) case fatality of 1%, 24 had a case fatality of 1-10%, 12 had a case fatality of 10-20%, and 12 had a case fatality of >20%.42

We have briefly reviewed, but not comprehensively vetted, some of the individual studies in this review. We note that some of these estimates are based on relatively small sample sizes and measure case fatality (i.e., the proportion of people diagnosed with pesticide poisoning who die) rather than mortality (i.e., the proportion of people who ingest pesticides who die).43

We used the estimates in this review to estimate the impact of two pesticide bans in Nepal.

In 2019, Nepal deregistered two pesticides: dichlorvos (estimated case fatality 32%, two studies, 25 cases) and the three-gram tablet form of aluminum phosphide (estimated case fatality 49%, two studies, 510 cases).44 CPSP collected data in Nepal on which pesticides were most commonly used in deaths by suicide prior to the bans.45 The average case fatality of other pesticides used in suicide in Nepal was 7%.46 This suggests that the case fatality of potential substitutes was about 80% lower than that of the banned pesticides.47

We use a range of 70-90% reduction in case fatality from targeted pesticide bans as a default input in our cost-effectiveness analysis.

We note some major limitations of this estimate:

• The estimated case fatality of dichlorvos is based on a small number of cases. However, we see the large number of deaths by suicide due to dichlorvos in Nepal as additional suggestive evidence that dichlorvos does in fact have a high case fatality.48
• We are unsure whether the mix of pesticides used in suicide is similar to Nepal in other countries where CPSP plans to work.
• This estimate may misstate the impact of pesticide bans if substitutes for the banned pesticide (i.e., the pesticides that take its place in the market) have a different case fatality than the average of other pesticides used in suicide.

(4) Most people who survive a suicide attempt do not later die by suicide.

Carroll, Metcalfe, and Gunnell 2014 is a systematic review and meta-analysis of 177 studies of the risk of repeat self-harm.49 It concluded that the risk of dying by suicide was 1.6% (95% CI 1.2-2.4) in the 12 months after a previous attempt, and 3.9% (3.2-4.8) after five years.50 We have not vetted the individual studies in this review but place weight on the results because of the tight confidence intervals and high number of studies.

We interpret this as strong evidence that reducing the case fatality of suicide attempts reduces the overall suicide rate, rather than delaying deaths by suicide.

What is the impact of preventing a suicide?

In order to assess the potential impact of this grant, we considered how we should compare the overall impact of preventing a suicide through pesticide poisoning to other outcomes we could support, such as preventing a death from malaria.

Making these comparisons is uncomfortable and challenging. We believe it is necessary to make explicit, quantitative comparisons between outcomes we could fund because:

• We have a finite pool of funding to allocate. Given that we can't support all opportunities, we focus on funding the ones where we believe we can have the most impact. In order to do that, we need to make comparisons between different positive outcomes to direct funding where it can achieve the most good, according to our values.
• We want to be transparent about the moral values underlying our recommendations.
• We hope that by being explicit about these comparisons, we will be more likely to reflect carefully on them and to find the best giving opportunities, according to our values.

We refer to the quantitative comparisons we make between different good outcomes as "moral weights." We discuss our reasons for setting moral weights in more detail here.

For this grant, we considered several key factors to compare the impact of pesticide suicide prevention with the impact of preventing deaths from malaria, including:

1. The age distribution of deaths from suicide in India is similar to the global age distribution of adult deaths from malaria.
2. The evidence we have seen suggests that suicide in general, and pesticide suicide in particular, appears often to be caused by a spontaneous decision.
3. A meta-analysis reports that the risk of death by suicide in the five years after a previous attempt is 3.9%.51

More information on studies we considered is here.

Based on these factors and discussion of the relevant studies within GiveWell's research team, we used an input that preventing one death from pesticide suicide has about 80% of the positive impact of preventing one adult death from malaria. We believe this estimate is a reasonable balancing of different considerations, but do not feel confident in the precise estimate.

Alternatives to deregistration

We investigated whether there were other options to prevent suicide by restricting access to pesticides without banning them.

We identified one large randomized controlled trial on encouraging safe pesticide storage, which has been hypothesized to reduce impulsive suicide by raising the barrier to accessing means of suicide.52

Pearson et al. 2017 is a cluster-randomized controlled trial testing the effectiveness of safe pesticide storage solutions to prevent suicide in Sri Lanka. Intervention households were given a lockable storage container and encouraged to store their pesticides in those containers.53 The study found no statistically significant difference in incidence of self-poisoning between the intervention and control groups (relative risk 0·93, 95% CI 0·80–1·08; p=0·33).54

We conclude there is strong evidence that the safe storage solution tested in the trial did not meaningfully reduce suicide rates, and this provides some evidence that other safe storage solutions may be similarly ineffective.

Potential negative/offsetting impacts

Effect on agricultural productivity

One of our biggest questions related to this grant was whether deregistering particular pesticides would reduce agricultural productivity, or increase agricultural input costs.

A back-of-the-envelope break-even calculation suggests that a 1% reduction in agricultural revenue from cultivation, or a 1.4% increase in input costs, would be equal in value to (i.e., would cancel out the benefits of) reducing the pesticide suicide burden by 60% in India. This estimate depends on a number of uncertain assumptions, particularly the numbers we use to compare the value of increasing economic welfare to that of preventing deaths.

We reviewed relevant literature and spoke with experts to better understand the extent to which substitutes were available for pesticides commonly used in suicide.

Direct evidence

We found two studies directly addressing the impact of targeted HHP bans on agricultural production and costs.

• Manuweera et al. 2008 compared agricultural yields for a number of crops in Sri Lanka with those from other South Asian countries between 1990 and 2003.55 They found that there was no noticeable change in crop yields relative to other countries following the banning of class I organophosphates in 1995, or endosulfan in 1998.56 While production costs rose, this was in line with the exchange rate and so is unlikely to be a result of the increased cost of replacement pesticides.57
• Cha et al. 2016 compared agricultural output in South Korea before and after a ban of paraquat in 2011 and concluded the ban had no detectable effect.58

We believe these studies provide some evidence that the impact of selective pesticide bans in these two countries was not large. However, given the many other factors influencing aggregate crop yields, we do not believe these studies provide conclusive evidence to rule out the possibility that pesticide bans could cause a small (1%) reduction in agricultural productivity.59 We therefore considered other relevant data points to weigh this concern.

Other relevant data points

Our best guess is that the effect on net agricultural productivity of deregistering HHPs is likely to be small. This is based on:

• Selective pesticide targeting. The burden of suicide appears to be concentrated in a limited number of pesticides. In Nepal over half of pesticide suicides were attributed to two active ingredients (out of about 900 active ingredients that CPSP told us are used globally).60 This suggests that large reductions in pesticide suicide may be achievable through restricting a small number of pesticides. We have not investigated whether the pesticides used in suicide are likely to comprise a disproportionate share of total pesticide use.
• Decision-makers have an incentive to increase agricultural yields and have banned pesticides in the past. Ministries of Agriculture, who make the decision to regulate pesticides, have a mandate to increase agricultural yields. Pesticides have been banned previously for reasons other than pesticide suicide.61 That suggests that Ministries of Agriculture consider the social costs of some pesticides, even excluding the potential suicide costs, to outweigh the benefits of their continued use. We have not seen the analysis on which these decisions were based.
• Availability of substitutes. We spoke with two people working in relevant fields who told us that substitutes are available for HHPs.62
• Pesticides are a small proportion of input costs. According to a large agricultural survey in India, pesticides currently account for ~7.5% of farmer input costs.63

On the other hand, we remain uncertain about the potential for deregistering pesticides to reduce net agricultural productivity.

• Small effect size of interest. A 1% decline in agricultural production is difficult to identify or rule out empirically, but would have large effects on economic welfare. This makes it difficult to be confident that deregistering particular pesticides would not have meaningful negative consequences.
• Learning costs and sub-optimal use. Pesticides commonly used for suicide may be more convenient, or have a different mechanism of application, in which case agricultural workers will incur some costs in learning how to use replacements. We have not thoroughly investigated this question.64

Bottom line

We apply a sizable downward adjustment (30%) to our cost-effectiveness analysis to account for our uncertainty about potential effects on agricultural production.

Effect on disease control

Some insecticides are important for controlling the spread of insect-borne diseases. Restricting these pesticides could therefore have negative consequences for vector control. However, there appears to be little overlap between the list of pesticides approved for use in vector control by WHO, and those most commonly used in suicide in Nepal (where we have the best available data).65

Impact of the previous grant to CPSP

Summary

CPSP's work over the last grant period played an important causal role in deregistration of two pesticides that together accounted for about 55% of pesticide suicides in Nepal. Our best guess is that these bans will prevent ~380 deaths each year in expectation.

On this basis, a back-of-the-envelope calculation suggested that our previous grant to CPSP was ~44x as cost-effective as GiveDirectly’s program, which provides unconditional cash transfers to poor households in low-income countries. That estimate relies on a number of uncertain assumptions, such as CPSP accelerating the policy changes it contributed to by nine years relative to the counterfactual. We therefore believe this estimate contains less information-value than cost-effectiveness estimates for our top charities, which limits its comparability. However, we believe CPSP's work during the previous grant period is likely to have been more cost-effective than additional funding to our top charities, even if this rough estimate is significantly off.

CPSP plans to gather additional data on method-specific suicide rates before and after the bans to estimate the effect of the bans on the suicide rate.

We believe CPSP's work has had less impact in India so far. CPSP provided input on a decision to ban a number of pesticides, but we expect those pesticides would likely have been deregistered without CPSP's input.66

Overall, we believe CPSP's work over the last grant period was broadly successful.

Previous forecasts

We previously forecast a 33-55% chance of significant regulation in Nepal (resolved yes), a 5-10% chance of significant regulation in India (resolved no), and a 15-35% chance of significant regulation in at least one Indian state (resolved no).

Those forecasts were intended to apply to whether regulation would change at all, rather than whether the regulation was attributable to CPSP's work. We believe the regulation in Nepal was directly attributable to CPSP's work, and so consider CPSP's work to be more successful than we expected.

The forecasts we made in August 2017 are below.

Confidence	Prediction	By Time	Resolution	Notes
Elie: 67%; James: 65%	We recommend a second grant to CPSP	July 1, 2019	No	CPSP's costs were lower than expected, so we did not recommend an additional grant until October 2020.
Elie: 33%; James: 55%	Conditional on CPSP entering Nepal, Nepal will pass legislation to ban at least one of the three pesticides most commonly used in suicide.	July 1, 2020	Yes	See below.
Elie: 5%; James: 10%	Conditional on CPSP entering India, India will pass legislation to ban at least one of the three pesticides most commonly used in suicide.	July 1, 2020	No	See below. India banned a number of pesticides in the previous grant period, but we are uncertain whether those pesticides were among those most commonly used in suicide.
Elie: 15%; James: 35%	Conditional on CPSP entering India, a state in India will pass legislation to ban at least one of the three pesticides most commonly used in suicide.	July 1, 2020	No	See below. India banned a number of pesticides in the previous grant period, but we are uncertain whether those pesticides were among those most commonly used in suicide.
James: 85% for each	Conditional on legislation to ban pesticides used in suicide being passed in Nepal / India, the pesticide suicide rate is lower in the combined three years after the ban than it is in the three years before the ban (as determined by national level data or representative survey data)	3 years after legislation passed	Not yet resolved
James: 40% for each	Conditional on legislation to ban pesticides used in suicide being passed in Nepal / India, the pesticide suicide rate is >10% lower in the combined three years after the ban than it is in the three years before the ban (as determined by national level data or representative survey data)	3 years after legislation passed	Not yet resolved
James: 20% for each	Conditional on legislation to ban pesticides used in suicide being passed in Nepal / India, the pesticide suicide rate is >15% lower in the combined three years after the ban than it is in the three years before the ban (as determined by national level data or representative survey data)	3 years after legislation passed	Not yet resolved

Work in Nepal

CPSP's work in Nepal focused on collecting data on the pesticides most commonly used in suicide, and working with relevant officials to deregister those pesticides.67

In February 2019, Nepal deregistered the two pesticides most commonly used in suicide there.

• Aluminum phosphide is a fumigant commonly used to fumigate grain stores.68 It was used in 34% of suicides for which data was available, the most of any individual pesticide.69 The three-gram tablet version of aluminum phosphide was deregistered; the powder form and larger tablets are still available.70
• Dichlorvos, an insecticide, was used in 22% of suicides for which data was available, the second most of any single pesticide.71 All forms of dichlorvos were deregistered.72

Four other pesticides were banned in 2019 for reasons other than suicide.73

Importing these pesticides became illegal in 2019, with a two-year grace period during which they could be used and sold within Nepal.74

Causal attribution

We are confident (95%) that dichlorvos and the three-gram tablet form of aluminum phosphide would not have been deregistered without CPSP's involvement.

Dr. Dilli Ram Sharma, the chair of Nepal's Plant Quarantine and Pest Management Center's technical committee,75 told us that prior to CPSP's involvement, (a) pesticide suicide was not a major focus for Nepal, and (b) it was not known which pesticides were most commonly used in suicide.76

Modelled impact of policy change

Our best guess is that the deregistration of dichlorvos and aluminum phosphide will prevent ~380 deaths each year in expectation, although we note some major limitations to this estimate below.

• According to data collected by CPSP, aluminum phosphide and dichlorvos were used in ~55% of all deaths from pesticide self-poisoning in Nepal in the period between April 14, 2019 and February 12, 2020,77 which we expect to translate to around 700 suicides per year from these two substances.78
• Dichlorvos has an estimated hospital case fatality of ~32% when ingested (i.e., 32% of patients who are taken to the hospital die), and aluminum phosphide has an estimated hospital case fatality of 49%.79 The average case fatality of other pesticides used in suicide attempts in Nepal (weighted by the number of suicide attempts) was ~7%.80 That suggests that if people switch to using other pesticides, the rate of death by suicide would decline.

Major limitations of this analysis:

• It is possible that dichlorvos is replaced by a pesticide that is more lethal than the weighted average of other pesticides used in suicide.
• We have not investigated case fatality estimates in detail. They could underestimate or overestimate the true chance of death from consuming pesticides because (i) they are based only on data collected in hospitals, meaning people who died (or survived) before arriving at the hospital are not counted, and (ii) they are based on different times and settings.81
• Only the three-gram tablet form of aluminum phosphide was banned. We believe there are good reasons to expect this ban to reduce the suicide rate. CPSP told us that aluminum phosphide reacts violently with water; we therefore expect it would be difficult to ingest either the powder form or larger (12-gram) tablets.82 We find the direct evidence that bans on aluminum phosphide tablets coincided with a decline in case fatality in India less compelling than the mechanistic explanation.83 We apply a discount in our cost-effectiveness analysis to account for aluminum phosphide still being available in other forms.84

Work in India

We are less confident that CPSP's work in the previous grant period had an impact in India.

• CPSP made limited progress in collecting data on pesticide suicide at the national level and so decided to focus on Maharashtra and Andhra Pradesh states, where it believes it can have more impact.85
• CPSP may have contributed to the decision in India to ban five pesticides commonly used in suicide, but we are not confident that the ban would not have happened without CPSP's contribution.86

Bottom-line cost-effectiveness estimate

Based on the potential benefits of CPSP's work in Nepal, a back-of-the-envelope calculation suggests that the previous grant to CPSP was about 44x as cost-effective as GiveDirectly’s program, which provides unconditional cash transfers to poor households in low-income countries. This estimate relies on a number of uncertain assumptions, and attempts to incorporate considerations that are particularly difficult to quantify. It therefore contains less information-value than cost-effectiveness estimates for our top charities, which limits its comparability. However, we believe CPSP's work during the previous grant period is likely to have been above the range of cost-effectiveness of our top charities even if this rough estimate is significantly off.

Calculations are available here.

Plan for follow-up and open questions

We expect to have conversations with CPSP every few months to check in on progress. We expect to consider whether to recommend renewing or extending this grant when CPSP has one year of funding remaining.

Open questions about the grant we plan to follow up on

• How are CPSP's activities progressing against planned milestones?
• Were the regulations CPSP contributed to in the previous grant period well enforced?
• Did the regulations CPSP contributed to in the previous grant period lead to reductions in the suicide rate?
• Are there promising opportunities to gather additional evidence on the agricultural effect of pesticide bans?

Other open questions we may investigate further

• How large are the non-suicide benefits from deregistering HHPs, such as reduced accidental poisonings, reduced morbidity, reduced treatment costs, or environmental benefits?
• How high are government costs of additional pesticide regulation?
• Would deeper review of the studies in Gunnell et al. 2017 meaningfully change our conclusions?
• Would deeper review of the case fatality estimates of different pesticides meaningfully change our conclusions?

Internal forecasts

We made a number of forecasts related to this grant, which are available in this spreadsheet.

Our process

We recommended the first grant to CPSP in August 2017. As this grant represented a large scale-up of CPSP's work, we investigated a number of questions in more depth.

• We investigated CPSP's track record over the previous grant period. We spoke with a pesticide regulator in Nepal, had several conversations with CPSP leadership and in-country staff, and reviewed documented evidence of CPSP's impact.
• We reviewed the evidence base behind pesticide suicide in more detail, and built a mechanistic model of the extent to which we'd expect reductions in the suicide rate to be counteracted by substitution of different methods.
• We reviewed the landscape of other potential funders and grant opportunities to address pesticide suicide.
• We reviewed relevant evidence for the effect of pesticide bans on agricultural productivity, and spoke with relevant experts.
• We reviewed CPSP's plans for expansion, and discussed them with CPSP.
• We incorporated the above information into forward-looking and backward-looking cost-effectiveness analyses.

Sources

Document	Source
Arjmand, "Considering policy advocacy organizations: Why GiveWell made a grant to the Centre for Pesticide Suicide Prevention," March 22, 2018	Source
Boedeker et al. 2020	Source (archive)
Bonvoisin et al. 2020	Source (archive)
Carroll, Metcalfe, and Gunnell 2014	Source (archive)
Centre for Effective Altruism, EffectiveAltruism.org, EA Funds: Global Health and Development Fund, "October 2020: Centre for Pesticide Suicide Prevention"	Source (archive)
Centre for Effective Altruism, Interview with Dr. Gamini Manuweera, former Sri Lankan Registrar of Pesticides, November 23, 2016	Source (archive)
Centre for Global Health Research, "Million Death Study (MDS)"	Source (archive)
Cha et al. 2016	Source
ChinaFile, The China NGO Project, "Fact sheet on China’s foreign NGO law," November 1, 2017	Source (archive)
Council on Foundations, "New Indian FCRA amendments impact foreign grants to Indian NGOs," November 12, 2020	Source (archive)
CPSP, Data analysis on pesticides used in suicide in Nepal, 2017-2020	Source
CPSP, Response to GiveWell questions, June 23, 2020	Source
CPSP, Response to GiveWell questions, November 17, 2020	Source
CPSP, Response to GiveWell questions, September 18, 2020	Source
Dawson et al. 2010	Source (archive)
Eddleston et al. 2006	Source
GiveWell, "Centre for Pesticide Suicide Prevention — General Support," 2017	Source
GiveWell, Back-of-the-envelope cost-effectiveness analysis of CPSP, 2021	Source
GiveWell, Calculation of potential agricultural impact of pesticide bans, 2020	Source
GiveWell, Cost-effectiveness analysis of CPSP's past impact, 2021	Source
GiveWell, CPSP forecasts, 2020	Source
GiveWell, CPSP three-year budget options, 2020	Source
GiveWell, Pesticide suicide method substitution back-of-the-envelope calculation, 2021	Source
GiveWell, Value of preventing a suicide, 2018	Source
GiveWell's non-verbatim summary of a conversation with Carole Hemmings, September 29, 2020	Source
GiveWell's non-verbatim summary of a conversation with CPSP, January 15, 2020	Source
GiveWell's non-verbatim summary of a conversation with CPSP, January 30, 2019	Source
GiveWell's non-verbatim summary of a conversation with CPSP, October 11, 2019	Source
GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020	Source
GiveWell's non-verbatim summary of a conversation with Professor Michael Eddleston, June 19, 2019	Source
Government of India, Ministry of Statistics and Programme Implementation, Key Indicators of Situation of Agricultural Households in India, 2014	Source (archive)
Gunnell et al. 2007	Source (archive)
Gunnell et al. 2017	Source (archive)
IPEN, "Pesticides"	Source (archive)
Knipe et al. 2017	Source (archive)
Manuweera et al. 2008	Source (archive)
Mew et al. 2017	Source (archive)
Moebus and Boedeker 2017 (preprint)	Source (archive)
Murali et al. 2009	Source
Observatory of Economic Complexity, International trade data, Pesticides, 2019	Source (archive)
Patel et al. 2012	Source (archive)
Pearson et al. 2015	Source (archive)
Pearson et al. 2017	Source (archive)
Pesticide Action Network International, "Strategic objectives"	Source (archive)
University of Edinburgh, Faculty profile of Professor Michael Eddleston	Source (archive)
US Environmental Protection Agency, R.E.D. Facts, Aluminum and Magnesium Phosphide, 1998	Source (archive)
van der Hoek and Konradsen 2006	Source (archive)
Weerasinghe et al. 2020	Source (archive)
WHO, Fact sheet detail, "Suicide," 2019	Source (archive)
WHO, List of WHO prequalified vector control products, 2020	Source (archive)
WHO, Preventing Suicide: A Global Imperative, 2014	Source (archive)
WHO, Preventing Suicide: A Resource for Pesticide Registrars and Regulators, 2019	Source (archive)
WHO, Safer Access to Pesticides for Suicide Prevention, 2016	Source (archive)

• 1

  "My work’s major aim is to reduce deaths from pesticide and plant self-poisoning in rural Asia, a cause of over 200,000 premature deaths each year and a key global means of suicide. To do this, I perform clinical trials in South Asian district hospitals to better understand the pharmacology and effectiveness of antidotes and community-based controlled trials to identify effective public health interventions. This work is complemented by large animal translational studies of antidotes in Edinburgh, work with sociologists and anthropologists to better understand the meaning of self-harm, and work with the World Health Organisation and Food & Agriculture Organisation to aid implementation. I also perform clinical and pre-clinical research in Edinburgh to improve treatment of other forms of poisoning (such as from cyanide, alcohol, and contrast media) by developing and/or testing novel antidotes." University of Edinburgh, Faculty profile of Professor Michael Eddleston

• 2

  See budget details in this spreadsheet, "Scen-4+UN+Reg" sheet.

• 3

  "The activities in each country will follow the same basic path of

  1. identifying problematic pesticides
  2. supporting regulators and agriculture ministry to identify effective alternatives, using globally accumulating data and tools currently in development
  3. supporting removal of the HHPs from agricultural use through regulation in a collaborative multi-stakeholder process
  4. setting up systems that will allow monitoring of the effect of the bans on suicides and agriculture
  5. CPSP will also work to provide clinical guidance on the best medical management of pesticide poisoned patients (via international guidelines that will be encouraged locally)"

  CPSP, Response to GiveWell questions, November 17, 2020

• 4

  "Professor Eddleston had a huge impact. We had really bad data – no local information on which pesticides were being used for suicide. Professor Eddleston was very helpful in providing the facts for me to move forward. His research was on pesticide suicides and he collected lots of data on which pesticides were used and what were the best treatments.

  "In a normal circumstance, a patient would come and a doctor would treat him on the symptoms, register the outcome and move on. Nobody was systematically compiling pesticide-specific suicide data apart from him. We would have had basic information about pesticide poisoning rates, but not known which chemicals were used.

  "He saw the same chemical kept coming up, came to me and we had lots of discussions. He was giving us more details than we’d ever had before. He had funds, resources and time which were all lacking in Sri Lanka.

  "He would be helpful elsewhere, particularly gathering data on the poisoning aspect – that’s his expertise. If your country had a serious pesticide poisoning situation he would be useful in terms of gathering and analysing data."

  Centre for Effective Altruism, Interview with Dr. Gamini Manuweera, former Sri Lankan Registrar of Pesticides, November 23, 2016

• 5
  • "Exports: In 2019 the top exporters of pesticides were China ($5.25B), United States ($4.24B), Germany ($4.09B), France ($4B), and India ($2.63B).." Observatory of Economic Complexity, International trade data, Pesticides, 2019
  • "Pesticides used in Nepal are primarily imported from China and India. Because there are no pesticides produced domestically in Nepal, there is no substantial industry opposition to national pesticide bans. In fact, the representatives from the private sector who were involved in the regulatory process agreed that the pesticides in question were dangerous and did not object to the bans that had been proposed." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020

• 6

  Chuanjiang Tao, Institute for the Control of Agrochemicals, Ministry of Agriculture and Rural Affairs, Beijing, China, email to Professor Michael Eddleston, October 22, 2020 (unpublished)

• 7
  • "The Foreign NGO Law mandates that foreign NGOs must register with the Ministry of Public Security (MPS) or its provincial-level equivalents before establishing an office within mainland China. If a foreign NGO wishes to carry out a “temporary activity” rather than open an office in China, it must file this information with the MPS. In both cases, foreign NGOs coordinate with a domestic Chinese organization in addition to the MPS. The time needed to complete registration or file for a temporary activity varies greatly.

    Foreign NGOs are permitted to work in economics, education, science, culture, health, sports, environmental protection, poverty, and disaster relief but “must not endanger China’s national unity, security, or ethnic unity; and must not harm China’s national interests, societal public interest”, or engage in or fund for-profit, political, or religious activities (Articles 3, 5). Foreign NGOs must be legally established overseas, have been active for at least two years, and be able to independently bear civil liability (Article 10)." ChinaFile, The China NGO Project, "Fact sheet on China’s foreign NGO law," November 1, 2017

  • "A new law that was signed on September 28, 2020 will greatly tighten and restrict the existing Foreign Contribution Regulation Act (FCRA). FCRA is the cornerstone law that regulates how nonprofits in India can receive foreign funding, including from U.S.-based foundations and corporations. …

    Any grant made to an Indian nonprofit would not allow re-granting or sub-granting. This means that funders who currently use FCRA-registered nonprofits as a re-granter to support other FCRA-registered Indian nonprofits may no longer do so. Additionally, Indian nonprofits who serve as a lead implementers on a given project may no longer create sub-grant relationships with other nonprofits using foreign funding. ...
    Previously, nonprofits receiving foreign funding under FCRA needed to create a bank account at any government-approved bank. Under the amended FCRA, all nonprofits must create and solely use a new account with the State Bank of India at New Delhi. The respective branch of the State Bank of India at New Delhi is required to report the contribution and its intended use to the central government. ...
    Previously, nonprofits receiving foreign funding could utilize up to 50% of foreign funds in a given fiscal year on administrative expenses. Under the amended FCRA, administrative expenses are now capped at 20% of foreign funds received. ...
    Currently, there is no way for nonprofits in India to voluntarily forfeit their FCRA registration. Under the amended FCRA, there is now a means to do so but assets previously created with foreign funds may then need to be transferred to the appropriate government arm." Council on Foundations, "New Indian FCRA amendments impact foreign grants to Indian NGOs," November 12, 2020

• 8

  "CPSP’s first application to ICMR was not approved, primarily due to questions around foreign involvement in the project. CPSP redrafted the application to include a response to those questions. In retrospect, CPSP believes that it and its collaborators in India should have anticipated those questions, but believes that its second application is much stronger. CPSP has employed staff and set up its data management system, so data collection is ready to begin once the project receives approval." GiveWell's non-verbatim summary of a conversation with CPSP, January 30, 2019

• 9

  "There is currently an unprecedented convergence of what were previously divergent interests in removing HHPs from use. This is bringing together UN agencies (FAO, WHO, UNEP), the Chemicals Conventions (Rotterdam, Stockholm), national and regional regulatory bodies, development partners, the private sector (pesticide industry, biopesticide industry, food retail, commodity traders), academic institutions and civil society. Using different mechanisms at their disposal, all these stakeholders are increasing their efforts to stop the use of particularly harmful pesticides in agricultural production, and to a lesser extent in public health. This shift happened on the back of accumulating scientific evidence of HHPs causing harm to health and environment, and of bans not affecting agricultural productivity." CPSP, Response to GiveWell questions, June 23, 2020

• 10

  We expect that pesticide regulation will more effectively reduce suicide when a higher proportion of pesticides used in suicide are banned, because of a lack of lethal alternatives.

• 11

  "CPSP implements a different type of program from work GiveWell has funded in the past. Namely, CPSP identifies the pesticides which are most commonly used in suicides and advocates for governments to ban the most lethal pesticides.

  "Because CPSP’s goal is to encourage governments to enact bans, its work falls into the broader category of policy advocacy, an area we are newly focused on. We plan to investigate or are in the process of investigating several other policy causes, including tobacco control, lead paint regulation, and measures to improve road traffic safety." Arjmand, "Considering policy advocacy organizations: Why GiveWell made a grant to the Centre for Pesticide Suicide Prevention," March 22, 2018

• 12

  "Close to 800 000 people die due to suicide every year." WHO, Fact sheet detail, "Suicide," 2019

• 13

  "We identified data from 108 countries (102 from WHO data, 6 from the literature). A conservative estimate based on these data indicates that there were approximately 110,000 pesticide self-poisoning deaths each year from 2010 to 2014, comprising 13.7% of all global suicides. A sensitivity analysis accounting for under-reporting of suicides in India resulted in an increased estimate of 168,000 pesticide self-poisoning deaths annually, that is, 19.7% of global suicides." Mew et al. 2017, p. 93

• 14
  • See Mew et al. 2017, p. 96, table 2, and WHO, Preventing Suicide: A Global Imperative, 2014, p. 17, table 1. We multiplied together the figures from the "% of global population" column in the WHO table and the "% of each region's population contributing to pesticide suicide estimate" in the Mew et al. table to arrive at the total percentage of the global population on which the pesticide suicide estimate was based (68.67%).
  • "The main limitation is the on-going absence of high quality method-specific suicide data for a number of the most populous countries including Indonesia, Pakistan, Nigeria, Bangladesh and Russia. This was particularly problematic in LMICs in the African and Eastern Mediterranean regions, where data were only available for 5.9% and 33.4% of the regions’ populations respectively. In these two regions, findings from studies that did not meet the inclusion criteria (Abula and Wondmikun, 2006, Ahmadi et al., 2010, Desalew et al., 2011, Islambulchilar et al., 2009, Keugoung et al., 2013, Khan, 2007, Khan et al., 2008, Khurram and Mahmood, 2008, Mohseni Saravi et al., 2013, Shahid and Hyder, 2008, Tahir et al., 2014, Toe et al., 2013, Z’gambo et al., 2016) indicate our lack of data results in a substantial underestimation of the percentage of pesticide suicides. The African region estimate is particularly unreliable as the two countries on which it is based, Mauritius and South Africa, are unrepresentative of the rest of the region. Nonetheless these regions are likely to have a limited impact on the global estimate as they currently account for less than 12% of the world's suicides (World Health Organisation, 2014).

    "A second potential limitation of this review is its reliance on WHO data. Under-reporting and misclassification affect the reliability of these data (World Health Organisation, 2014). However, where national published data were available to compare with WHO data (8 countries), the estimates of pesticide suicides differed by less than 5% between the two sources. Furthermore the extent to which WHO estimates are based on the same sources as the national published data is unknown. In comparison, small, focussed studies indicate the WHO data may substantially underestimate the burden of pesticide self-poisoning, particularly in rural areas (Abula and Wondmikun, 2006, Keugoung et al., 2013, Toe et al., 2013).

    "The third limitation is our crude assumption that the percentage of suicides due to pesticides within each country in a region is likely to be similar." Mew et al. 2017, p. 99

• 15

  "The availability of country-specific estimates of the number /% of pesticide suicides varies from region to region. For example, estimates of the proportion of total suicides due to pesticide poisoning for African LMICs are based on countries that comprise only 5.9% of that region's population." Mew et al. 2017, p. 96, table 2, footnote B

• 16
  • "The Million Death Study (MDS) is one of the largest studies of premature mortality in the world. The MDS is an ongoing study that is conducted in India, where, like most low- and middle-income countries, the majority of deaths occur at home and without medical attention." Centre for Global Health Research, "Million Death Study (MDS)"
  • "A nationally representative mortality survey determined the cause of death occurring in 1·1 million homes in 6671 small areas chosen randomly from all parts of India. Two trained physicians independently assigned codes to the causes of death, based on a nonmedical surveyor’s field interview with household respondents." Patel et al. 2012, p. 1

• 17
  • "The suicides in this study were of all people who had died between 2001 and 2003 and whose causes of death were eventually assigned to ICD-10 codes X60 to X84 (intentional self harm)." Patel et al. 2012, p. 3
  • "For suicide deaths at ages 15 years and older 40% percent of male suicides and 56% of female suicides occurred at ages 15–29 years." Patel et al. 2012, p. 1

• 18

  “One of the key methods of suicide in LMICs, particularly in countries with a high proportion of rural residents engaged in small-scale agriculture, is pesticide self-poisoning.” WHO, Preventing Suicide: A Global Imperative, 2014, p. 24

• 19

  "At this point, CPSP is the only NGO currently working on pesticide suicide reduction in Nepal. There is a local doctor working on a pesticide suicide study in Nepal but it is a small-scale study that is collecting data from only one hospital." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 4

• 20
  • The Pesticide Action Network International does not specifically mention suicide in its list of strategic objectives. Pesticide Action Network International, "Strategic objectives"
  • In its webpage on pesticides, the International POPS Elimination Network (IPEN) does not mention pesticide suicide. IPEN, "Pesticides"

• 21

  "CPSP plans to collect data in India and Nepal on which pesticides are most commonly used in suicide attempts, and are most likely to result in death. CPSP plans to use this data to help the governments of India and Nepal decide which pesticides to ban, with the intention of reducing suicide rates." GiveWell, "Centre for Pesticide Suicide Prevention — General Support," 2017

• 22
  • "We identified 27 studies undertaken in 16 countries—five low-income or middle-income countries (Bangladesh, Colombia, India, Jordan and Sri Lanka), and 11 high-income countries (Denmark, Finland, Germany, Greece, Hungary, Ireland, Japan, South Korea, Taiwan, UK, and USA). Assessments largely focused on national bans of specific pesticides (12 studies of bans in six countries—Jordan, Sri Lanka, Bangladesh, Greece [Crete], South Korea, and Taiwan) or sales restrictions (eight studies of restrictions in five countries— India, Denmark, Ireland, the UK and the USA)." Gunnell et al. 2017, p. e1026
  • "National bans on commonly ingested pesticides were assessed in six countries (one study focused on the Greek island of Crete; table 2). Data for Sri Lanka relate to two series of bans: the first in the 1990s, the second during 2008–10. Four of these studies used appropriate analytical methods. In all areas where bans had been assessed, pesticide self-poisoning accounted for a high proportion of total suicides (>15%)." Gunnell et al. 2017, p. e1030

• 23

  "In all countries except Greece, the bans were followed by reductions in pesticide suicides. In Bangladesh, Sri Lanka, and South Korea, where the timing of the bans on specific pesticides was reported and where investigators assessed the effect of regulations on overall suicides, there were simultaneous declines in overall suicide rates. The cumulative effect of Sri Lanka's pesticide regulations was estimated to have prevented 93 000 suicide deaths in 20 years up to 2015. In Bangladesh, overall injury rates including suicides decreased by 24% (separate data for suicides were not reported). In the 3 years after a ban on paraquat in South Korea, the decline in pesticide suicides following the ban contributed to more than half of the decrease in overall suicides that occurred after the ban." Gunnell et al. 2017, p. e1030

• 24

  "Because of the range of different interventions, settings, and differences in the incidence of suicide by pesticide poisoning and the contribution of pesticide self-poisoning to overall suicide rates in different countries, we undertook a narrative synthesis of the data presented in each paper." Gunnell et al. 2017, p. e1028

• 25

  See "Track record" in the list of factors we took into account in the "Forecasts of chance of success" section.

• 26

  See, for example, van der Hoek and Konradsen 2006 and Dawson et al. 2010, both of which analyzed Sri Lankan hospital records for poisoning patients.

• 27

  "In the 10 years after 1995, Sri Lanka’s suicide rates declined by 50% (Figure 1)." Gunnell et al. 2007, p. 1235

• 28
  • "From the late 1970s until the early 1990s, WHO Class I (‘extremely or highly toxic’); organophosphorus (OP) insecticides such as parathion, methyl parathion, monocrotophos and methamidophos were the commonest poisons taken in fatal self-harm. The Registrar of Pesticides banned methyl parathion and parathion in 1984 and over the following years gradually phased out all the remaining Class I organophosphate pesticides, culminating in July 1995 with bans on the remaining Class I pesticides monocrotphos and methamidophos." Gunnell et al. 2007, p. 1237
  • "There appeared to be little impact on suicides of the bans placed on methyl parathion and parathion in 1984, other than perhaps a slowing of the rapid rise in suicide rate noticed between 1961 and 1983. However, the ban on the final permitted class I pesticides methamidophos and monocrotophos (1995) and the class II pesticide endosulfan (1998) were both followed by marked reductions in overall suicides." Gunnell et al. 2007, p. 1237

• 29

  "Overall suicide mortality dropped by 21% between 2011 and 2015, from 18.3 to 14.3 per 100,000." Knipe et al. 2017, p. 1

• 30

  "Objective: To investigate the effect of 3-year phased bans of the pesticides dimethoate and fenthion in 2008–2010, and paraquat in 2009–2011, on suicide mortality in Sri Lanka." Knipe et al. 2017, p. 1

• 31
  • "The second limitation of our analysis is that the data are ecological, thus limiting causal inference. Whilst the timing of reductions in suicide rates corresponds with pesticide related interventions and such downturns did not appear to be associated with changes in other risk factors for suicide, we cannot rule out the impact of other (unrecognised) factors in the absence of a control population. Our data are, however, supported by recent declines in the case-fatality of pesticide poisoning in Sri Lanka. Furthermore, data from two other Asian countries where pesticide regulation has not occurred—India and Korea—reveal differing trends in suicide. In India, Sri Lanka’s closest neighbour, self poisoning (mainly insecticides) accounts for 37% of suicides and there has been no equivalent decline in suicide rates. Suicide rates in India were 9.7 per 100,000 in 1995, 10.8 per 100,000 in 1998 and 10.3 per 100,000 in 2005. In Korea, rates of pesticide suicide doubled between 1991 and 2001." Gunnell et al. 2007, p. 1240
  • "Time series analyses of data from a single country, as we have here, must be interpreted with caution. There are trends over time in many things, and similar trends in two measures provide no convincing evidence of one causing the other, or of a common underlying cause." Knipe et al. 2017, p. 9

• 32
  • "We obtained data on the number of suicides in Sri Lanka from the following sources: (i) total suicides and suicide rates between 1940 and 1975 from two previous analyses of suicide in Sri Lanka both based on data from Sri Lanka’s Registrar General; (ii) age-, sex- and method-specific suicide data from 1975 to 2005 from the Department of Police, Division of Statistics, Sri Lanka." Gunnell et al. 2007, p. 1236
  • "An important weakness in our analysis is the poor quality of the method-specific suicide data. Over the period of time covered by the data, the categories used to identify the specific methods used for suicide changed. Furthermore, extensive use was made of the ‘other means’ of suicide category, despite the most commonly used methods of suicide in Sri Lanka (i.e. hanging, poisoning, drowning, burning and jumping in front of trains) being available as specific coding categories throughout the study period." Gunnell et al. 2007, p. 1239
  • "One of the strengths of this study is the availability of age, sex and method specific suicide data at the national level. This wealth of data is unusual for a LMIC country. This dataset, however, is not without its limitations…. A further limitation is that we may not be capturing the true incidence of suicide. There are no studies which have investigated the quality or reliability of Sri Lanka’s suicide data. Anecdotal evidence from our field research indicates that the quality of suicide data may vary by police departments, but we have no evidence to suggest that the data quality has changed over time." Knipe et al. 2017, p. 9

• 33

  "There appeared to be little impact on suicides of the bans placed on methyl parathion and parathion in 1984, other than perhaps a slowing of the rapid rise in suicide rate noticed between 1961 and 1983. However, the ban on the final permitted class I pesticides methamidophos and monocrotophos (1995) and the class II pesticide endosulfan (1998) were both followed by marked reductions in overall suicides." Gunnell et al. 2007, p. 1237

• 34
  • "Nevertheless, it is of note that deaths by hanging, the second commonest method of suicide in Sri Lanka, rose throughout the study period. This provides some evidence that favourable trends in overall suicides were driven by a reduction in poisoning deaths rather than some other factor influencing all suicides regardless of method." Gunnell et al. 2007, p. 1239
  • "Whilst we observed some evidence of method substitution, the rise in suicide by other methods was much smaller than the fall in the number of pesticide deaths, resulting in an overall 21% absolute decline in all suicides over five years in 2011–2015." Knipe et al. 2017, p. 9

• 35

  Dawson et al. 2010, a prospective cohort study of 9,302 pesticide poisoning patients in Sri Lankan hospitals between April 2002 and November 2008, found that dimethoate, paraquat, and fenthion (the three pesticides banned between 2008 and 2011) were responsible for 47% of deaths from pesticide self-poisoning over the period, and were substantially more likely to result in death than the average for pesticide self-harm.

  • "Methods and Findings: We examined the case fatality of different agricultural pesticides in a prospective cohort of patients presenting with pesticide self-poisoning to two clinical trial centers from April 2002 to November 2008. Identification of the pesticide ingested was based on history or positive identification of the container. A single pesticide was ingested by 9,302 patients. A specific pesticide was identified in 7,461 patients; 1,841 ingested an unknown pesticide. In a subset of 808 patients, the history of ingestion was confirmed by laboratory analysis in 95% of patients. There was a large variation in case fatality between pesticides—from 0% to 42%. This marked variation in lethality was observed for compounds within the same chemical and/or WHO toxicity classification of pesticides and for those used for similar agricultural indications." Dawson et al. 2010, p. 1
  • "For those ingesting an identified pesticide, just three compounds with relatively high case fatality (paraquat, dimethoate, fenthion) were responsible for 17.6% of total admissions but 47% of the total deaths." Dawson et al. 2010, p. 3
  • "The overall mortality for pesticide self-poisoning (including patients who had ingested an unidentified pesticide) was 10.1% (CI [confidence interval] 9.5–10.8)." Dawson et al. 2010, p. 3.
  • See Dawson et al. 2010, pp. 4-5, table 2:
    • Paraquat: case fatality 42.7% (95% CI 38.6-46.9)
    • Dimethoate: case fatality 20.6% (95% CI 17.9-23.6)
    • Fenthion: case fatality 14.8% (95% CI 10.5-19.9)
• van der Hoek and Konradsen 2006 is a retrospective analysis of 8,110 hospital admissions for acute poisoning in Sri Lanka between 1990 and 2002. It finds endosulfan had a higher case fatality (29.3%; see p. 227, table 2) and caused more deaths than any other specific type of pesticide.
  • "Methods. Time series of incidence of acute poisoning based on retrospective in-patient records of six government hospitals in southern Sri Lanka from 1990 to 2002. Results. Data of 8,110 admissions for acute poisoning were available for analysis." van der Hoek and Konradsen 2006, p. 225
  • "Endosulfan was the single most important cause of death in this study population with extremely high case fatality ratio (Table 2), and it is therefore not surprising that the overall mortality rate of pesticide poisoning went down from 26.41 (95% CI, 23.77–29.05) per 100,000 over 1990–1998, to 16.34 (95% CI, 13.94–18.74) per 100,000 over 1999–2002." van der Hoek and Konradsen 2006, p. 228

• 36

  "We interviewed 268 patients who were conscious soon after admission and willing to be interviewed about their reasons for choosing the poison they had ingested. They had ingested oleander seeds (137), paraquat (24), pesticides other than paraquat (41), medicines (63), or others poisons (1 hydrocarbon, 1 alkali,1 plant). With only one patient in each of these groups, these three patients are not analyzed with the patients in the four other poison categories." Eddleston et al. 2006, p. 2

• 37

  See Eddleston et al. 2006, p. 7, table 2.

• 38

  "Similarly, the majority of patients ingesting paraquat, pesticides or medicines (75%, 71%, 84%, respectively) obtained the poison from their home. Few patients (17%, 20%, and 16%) had bought the poison from a shop for the attempt. The particular pesticide was sometimes chosen by the shop assistant." Eddleston et al. 2006, p. 2

• 39

  "We interviewed 268 patients who were conscious soon after admission and willing to be interviewed about their reasons for choosing the poison they had ingested. They had ingested oleander seeds (137), paraquat (24), pesticides other than paraquat (41), medicines (63), or others poisons (1 hydrocarbon, 1 alkali, 1 plant). With only one patient in each of these groups, these three patients are not analyzed with the patients in the four other poison categories. Not all patients could be interviewed–we saw a selected opportunistic sample of patients based on their medical fitness, willingness to enter the trial and be interviewed, and the staff time and availability to carry out the interview. Inevitably, this resulted in selection bias against more severely ill patients and those under the influence of alcohol (almost exclusively male). The 268 patients differed from the whole population of poisoned patients by being more likely to be female, young, have ingested poisons other than non-paraquat pesticides, and survive (Table 1)." Eddleston et al. 2006, p. 2

• 40

  "Pesticide registrars and regulators should work closely with national poison centres (where these exist) and the public health units of ministries of health to carry out a situation analysis to determine the number of deaths and hospital admissions due to pesticide poisoning and to identify the specific pesticides and pesticide formulations most commonly involved. Particular attention should be paid to those pesticides most often ingested in self-poisoning (both in suicides and suicide attempts). Identification of these products may also be achieved through high-quality community, hospital and mortuary-based studies of a consecutive series of pesticide suicide deaths or serious poisonings. Such studies should ideally be nationally representative, covering the range of farming practices and settings (rural/urban). Further assessments every 3−5 years to assess the impact of regulatory action and changes in the pesticides commonly used for suicide would bring additional benefits." WHO, Preventing Suicide: A Resource for Pesticide Registrars and Regulators, 2019, p. 25

• 41

  "Methods: We searched literature databases as well as the internet for studies on case-fatality and severity scores of pesticide poisoning. Studies published between 1990 and 2014 providing information on active ingredients in pesticides or chemical groups of active ingredients were included. The variability of case-fatality-ratios was analyzed by computing the coefficient of variation as the ratio of the standard deviation to the mean.

  "Findings: We identified 145 studies of which 67 could be included after assessment. Case-fatality-ratio (CFR) on 68 active ingredients and additionally on 13 groups of active ingredients were reported from 20 countries. Mean CFR for group of pesticides is 12 %, for single pesticides 15 %. Of those 12 active ingredients with a CFR above 20 % only two are WHO-classified as “extremely hazardous” or “highly hazardous”, respectively. Two of seven pesticides considered “unlikely to present hazard in normal use” show CFR above 20 %. The variability of reported case fatality was rather low." Moebus and Boedeker 2017 (preprint), p. 2

• 42

  See Moebus and Boedeker 2017 (preprint), p. 16, table 4.

• 43
  • See Moebus and Boedeker 2017 (preprint), pp. 9-12, table 1 for the number of cases estimates were based on for each pesticide.
  • "Our review has some limitations. The reliability of CRF [sic] may be limited by selection bias, say that primarily severe poisonings were subject to treatment and therefore a higher case fatality is observed in studies. We tried to avoid this possible bias by excluding pure case studies from this review." Moebus and Boedeker 2017 (preprint), p. 19

• 44
  • See the "Work in Nepal" section for more details on the deregistration of dichlorvos and aluminum phosphide.
  • See Moebus and Boedeker 2017 (preprint), p. 10, table 1 for case fatality and number of cases for dichlorvos and aluminum phosphide.

• 45

  See CPSP, Data analysis on pesticides used in suicide in Nepal, 2017-2020 for CPSP's data.

• 46

  See this spreadsheet, "Nepal pesticide suicide distribution" sheet, cell R31.

• 47

  See this spreadsheet, "Method substitution BOTEC" sheet, cell E14.

• 48

  See this spreadsheet, "Nepal pesticide suicide distribution" sheet, row 12.

• 49

  "Background: Non-fatal self-harm is one of the most frequent reasons for emergency hospital admission and the strongest risk factor for subsequent suicide. Repeat self-harm and suicide are key clinical outcomes of the hospital management of self-harm. We have undertaken a comprehensive review of the international literature on the incidence of fatal and non-fatal repeat self-harm and investigated factors influencing variation in these estimates as well as changes in the incidence of repeat self-harm and suicide over the last 30 years.

  "Methods and Findings: Medline, EMBASE, PsycINFO, Google Scholar, article reference lists and personal paper collections of the authors were searched for studies describing rates of fatal and non-fatal self-harm amongst people who presented to health care services for deliberate self-harm. Heterogeneity in pooled estimates of repeat self-harm incidence was investigated using stratified meta-analysis and meta-regression. The search identified 177 relevant papers." Carroll, Metcalfe, and Gunnell 2014, p. 1

• 50

  "The risk of suicide in the 12 months after an index attempt was 1.6% (CI 1.2–2.4) and 3.9% (CI 3.2–4.8) after 5 years. The estimated 1 year rate of non-fatal repeat self-harm was 16.3% (CI 15.1–17.7). This proportion was considerably lower in Asian countries (10.0%, CI 7.3–13.6%) and varies between studies identifying repeat episodes using hospital admission data (13.7%, CI 12.3–15.3) and studies using patient report (21.9%, CI 14.3–32.2). There was no evidence that the incidence of repeat self-harm was lower in more recent (post 2000) studies compared to those from the 1980s and 1990s." Carroll, Metcalfe, and Gunnell 2014, p. 1

• 51

  "The risk of suicide in the 12 months after an index attempt was 1.6% (CI 1.2–2.4) and 3.9% (CI 3.2–4.8) after 5 years." Carroll, Metcalfe, and Gunnell 2014, p. 1

• 52

  "The idea behind the communal pesticide storage demonstration project in rural southern India was a simple one. Keeping pesticides out of sight and beyond the easy access of households might reduce the occurrence of suicides and suicide attempts by means of pesticide ingestion. The project was the first of its kind in India. The aim was to investigate whether the safe storage of pesticides away from people’s homes, in a communal unit, could indeed contribute to reducing the risk of suicides and suicide attempts." WHO, Safer Access to Pesticides for Suicide Prevention, 2016, p. 14

• 53

  "We did a community-based, cluster-randomised controlled trial in a rural area of North Central Province, Sri Lanka. Clusters of households were randomly assigned (1:1), with a sequence computer-generated by a minimisation process, to intervention or usual practice (control) groups. Intervention households that had farmed or had used or stored pesticide in the preceding agricultural season were given a lockable storage container. Further promotion of use of the containers was restricted to community posters and 6-monthly reminders during routine community meetings. The primary outcome was incidence of pesticide self-poisoning in people aged 14 years or older during 3 years of follow-up. Identification of outcome events was done by staff who were unaware of group allocation. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT1146496." Pearson et al. 2017, p. 1863

• 54

  "Between Dec 31, 2010, and Feb 2, 2013, we randomly assigned 90 rural villages to the intervention group and 90 to the control group. 27 091 households (114 168 individuals) in the intervention group and 26 291 households (109 693 individuals) in the control group consented to participate. 20 457 household pesticide storage containers were distributed. In individuals aged 14 years or older, 611 cases of pesticide self-poisoning had occurred by 3 years in the intervention group compared with 641 cases in the control group; incidence of pesticide self-poisoning did not differ between groups (293·3 per 100 000 person-years of follow-up in the intervention group vs 318·0 per 100 000 in the control group; rate ratio [RR] 0·93, 95% CI 0·80–1·08; p=0·33). We found no evidence of switching from pesticide self-poisoning to other forms of self-harm, with no significant difference in the number of fatal (82 in the intervention group vs 67 in the control group; RR 1·22, 0·88–1·68]) or non-fatal (1135 vs 1153; RR 0·97, 0·86–1·08) self-harm events involving all methods." Pearson et al. 2017, p. 1863

• 55

  "METHODS: We used data from the World Resources Institute to compare the yields of the main crop groups in Sri Lanka with those from surrounding South Asian countries for 1980–2005. We also examined data from the Sri Lankan Department of Census and Statistics to examine the yields of 13 specific vegetable crops and rice for 1990–2003, along with the costs of rice production." Manuweera et al. 2008, p. 492

• 56

  “The yields of the main crop groups in Sri Lanka showed no obvious drop in productivity in the years after the main bans were instituted (1995 and 1998). There was substantial annual fluctuation in estimated yields, but these did not coincide with the bans and were no larger than the fluctuations in other countries. On average, the Sri Lankan yields for cereals and pulses are higher and those for roots and tubers are lower than those of the neighboring countries (Figure 2).” Manuweera et al. 2008, p. 493

• 57

  "Production costs for paddies within the NCP have increased steadily over time. However, there was no change in this rate that coincided with the bans; in contrast, a significant increase in production costs occurred because of rising fuel prices and deterioration of the exchange rate around 2002–2003." Manuweera et al. 2008, p. 493

• 58

  The data show a decline in vegetable yields in 2012, which returned to normal levels in 2013 (see Cha et al. 2016, p. 474, figure 1a). We do not know what caused the decline, but given the quick recovery, we believe it is unlikely to have been lack of access to paraquat.

  • “Agricultural crop yields increased slightly over the study period and the results were similar for different types of crops (Supplementary Figure 1S).” Cha et al. 2016, p. 473
  • “In addition, although there were some concerns that paraquat bans may adversely affect agricultural output, our results show no evidence that crop yield was affected by the paraquat ban, which is consistent with findings in Sri Lanka.” Cha et al. 2016, p. 477

• 59

  Our view was informed by inspecting figure 3 in Manuweera et al. 2008.

• 60
  • See this spreadsheet, "NFSL+POLICE tox" sheet, for the mix of pesticides used in suicide in Nepal. The analysis identifies dichlorvos and phosphide as responsible for 39 and 29 pesticide self-poisoning deaths, respectively, out of a total of 114 total pesticide self-poisoning deaths in a 15-month period.
  • "There are around 900 pesticide active ingredients in use globally at present." CPSP, Response to GiveWell questions, September 18, 2020

• 61

  See Pearson et al. 2015, p. 58, table 1, "Import bans of pesticides in Sri Lanka 1970–2008."

• 62
  • "GiveWell shared a list of highly toxic pesticides with Ms. Hemming. She said that nothing on the list seemed crucial to farmers because most of the pesticides would have substitute products." GiveWell's non-verbatim summary of a conversation with Carole Hemmings, September 29, 2020, p. 3
  • "Class I Organophosphates were banned in 1995. They are broad spectrum insecticides which kill a variety of insects. There were lots of alternatives so it was quite obvious that it wouldn’t have a large impact on crop yields without quantifying exactly. There were more than 120 different active ingredients then and 400-500 different products. There were about 70-80 different insecticides. If you looked at the benefits, particularly the number of suicides, it was huge. Sri Lanka was top five in the world in suicide death rates. We didn’t think the cost-benefit was close enough to warrant full quantification." Centre for Effective Altruism, Interview with Dr. Gamini Manuweera, former Sri Lankan Registrar of Pesticides, November 23, 2016. (This interview was conducted by James Snowden, who led this investigation for GiveWell when he worked at the Centre for Effective Altruism.)

• 63

  See Government of India, Ministry of Statistics and Programme Implementation, Key Indicators of Situation of Agricultural Households in India, 2014, table 8, p. A-13, for average monthly expenses on plant protection chemicals.

• 64

  "Dichlorvos is a popular, low-cost insecticide used by farmers in Nepal to protect their crops. Unlike most other pesticides, crops that have been sprayed with dichlorvos can be safely consumed three days after spraying, rather than requiring a waiting period of up to several weeks. CPSP's report showed that dichlorvos was the most commonly used pesticide in deaths by suicide in Nepal. As with aluminum phosphide, the pesticide regulator of Nepal did not have study data and was unaware that dichlorvos was one of the top two pesticides being used in suicides prior to CPSP's involvement." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 2
  

• 65

  We reviewed the list of WHO prequalified vector control products and compared it to the pesticides most commonly used in suicide in Nepal (the country for which we have the best data). Of pesticides approved by WHO, only alphamethrin/cypermethrin were detected in forensic autopsies of suicide cases in Nepal, causing 40 deaths (4.5% of total deaths by suicide). See this spreadsheet, "Nepal pesticide suicide distribution" sheet, for details (rows 23 and 24 for suicide deaths from alphamethrin and cypermethrin; cell I32 for percentage of suicide deaths caused by these ingredients).

• 66

  "A few years ago, non-governmental organizations (NGOs) presented India's government with a list of ~100 pesticides to ban, on the basis of being banned elsewhere. This followed an Anupam Verma report in 2016, which reviewed 66 pesticides and recommended banning eighteen of them. However, these bans were not completed until recently. CPSP submitted a document to the governmental committee chaired by Malhotra in India to explain the benefits of banning HHPs for preventing suicides (in addition to the other, already-acknowledged benefits for the environment and health). Dr. Utyasheva led CPSP's work on this document.

  "Twelve pesticides were banned by the government in 2018, and an additional 6 are scheduled to be banned in late 2020. CPSP expects to see a reduction in pesticide suicide as a result of these bans, as they include five HHPs that play a large role in pesticide suicide in India: methyl parathion, phorate, phosphamidon, dichlorvos, and triazophos. There are now only three or four remaining pesticides that CPSP believes are particularly important to ban in India, including monocrotophos.

  "Because CPSP was asked by civil society groups to present evidence to inform the committee's decisions, and those decisions were made shortly after CPSP's contributions, CPSP believes that its work contributed to the deliberations of the committee and consequently to the adopted decisions." GiveWell's non-verbatim summary of a conversation with CPSP, January 15, 2020, pp.3-4

• 67

  From our page on the grant we made to CPSP in 2017: "CPSP plans to collect data in India and Nepal on which pesticides are most commonly used in suicide attempts, and are most likely to result in death. CPSP plans to use this data to help the governments of India and Nepal decide which pesticides to ban, with the intention of reducing suicide rates."

• 68

  "Aluminum and magnesium phosphide are fumigants used to control insects and rodents. They are primarily used for indoor fumigation of raw agricultural commodities, animal feeds, processed food commodities, and nonfood commodities in sealed containers or structures, and for outdoor fumigation of burrows to control rodents and moles in non-domestic areas, noncropland, and agricultural areas." US Environmental Protection Agency, R.E.D. Facts, Aluminum and Magnesium Phosphide, 1998

• 69

  See this spreadsheet, "Nepal pesticide suicide distribution" sheet, cell K27.

• 70

  "CPSP also informed Nepalese regulators that aluminum phosphide can be purchased in larger, 12 g tablets or in powder form instead, both of which are more difficult to ingest. As a result, the Nepalese regulatory body decided to ban only the smaller, 3 g tablets. Importation of the tablets became illegal immediately, although tablets that had already been imported at the time of the ban can continue to be sold during a two-year grace period, after which the sale of the tablets will also become illegal. After the two-year grace period ends, a decline in the suicide rate would be evidence of the success of the ban." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 2

• 71

  See this spreadsheet, sheet "Nepal pesticide suicide distribution," cell K12.
  

• 72

  "After receiving CPSP's report, Nepalese regulators followed its recommendations and implemented bans on 3 gram aluminum phosphide tablets and dichlorvos in 2019." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 1

• 73

  "Nepal's 2019 pesticide bans also included triazophos, carbofuran, carbaryl, and benomyl, although the rationale for these additional bans was unrelated to CPSP's work on pesticide suicide and instead revolved around the carcinogenic nature of these chemicals." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 2

• 74

  "Importation of the tablets became illegal immediately, although tablets that had already been imported at the time of the ban can continue to be sold during a two-year grace period, after which the sale of the tablets will also become illegal. After the two-year grace period ends, a decline in the suicide rate would be evidence of the success of the ban." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 2

• 75

  "The process for implementing a pesticide ban in Nepal begins with a recommendation from the Plant Quarantine and Pest Management Center's technical committee, which is led by the Joint Secretary (Chief of Center). The technical committee also includes representatives from the Nepal Agriculture Research Council, the Epidemiology and Disease Control Division within its Ministry of Health, and an industry group called the Nepal Pesticide Association.

  "The technical committee assesses pesticides individually, discussing the risks and benefits of each, along with potential alternatives that would be available to farmers if it was banned. If the technical committee decides that a ban would be appropriate, it presents its case to a pesticide board, which bears the ultimate authority for approving a ban. The board includes members of industry, scientists, farmers, and others.

  "In the case of the aluminum phosphide and dichlorvos bans, Dr. Sharma, who was chairing the technical committee at the time, requested that a representative from CPSP be directly involved in making the presentation to the pesticide board. After CPSP's presentation, the board unanimously agreed to ban the two chemicals." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 3

• 76
  • "Prior to CPSP's involvement, regulators in Nepal were aware that pesticide suicide was a problem and had seen data on pesticides that were used in suicides in other countries, but they did not have data on which pesticides were being used in suicides in Nepal. After receiving CPSP's report, Nepalese regulators followed its recommendations and implemented bans on 3 gram aluminum phosphide tablets and dichlorvos in 2019." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 1
  • "Prior to CPSP's involvement, suicide prevention was not a primary focus for Nepal's pesticide regulatory body. Most pesticide bans have been implemented because chemicals were determined to be hazardous to human health or the environment. In one case, a chemical called endosulfan was being poured into bodies of water to kill fish. Another chemical, called dicofol, was banned after the Rotterdam Convention recommended that chlorinated pesticides no longer be used." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 3
  • "Prior to CPSP's report, the Nepalese government had not seen study data suggesting that aluminum phosphide was being used for suicide, and preventing pesticide suicides had not been one of their regulatory goals." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 2
  • "As with aluminum phosphide, the pesticide regulator of Nepal did not have study data and was unaware that dichlorvos was one of the top two pesticides being used in suicides prior to CPSP's involvement." GiveWell's non-verbatim summary of a conversation with Dr. Dilli Ram Sharma, December 21, 2020, p. 2

• 77

  See here for deaths from dichlorvos during this period, and here for deaths from aluminum phosphide during this period. Together the two substances were responsible for 491 deaths, or 55% of total deaths in this period (891).

• 78

  See here for expected annual aluminum phosphide deaths and here for expected annual dichlorvos deaths without the bans. We arrived at these individual numbers by first annualizing the figures in the data gathered by CPSP, then multiplying each by 1.2 to account for likely underreporting. Together these total approximately 700 deaths (431 + 277 = 708).

• 79

  See here for aluminum phosphide and here for dichlorvos.
  

• 80

  See this spreadsheet, "Nepal pesticide suicide distribution" sheet, cell R31.

• 81
  • "Our review has some limitations. The reliability of CRF [sic] may be limited by selection bias, say that primarily severe poisonings were subject to treatment and therefore a higher case fatality is observed in studies. We tried to avoid this possible bias by excluding pure case studies from this review." Moebus and Boedeker 2017 (preprint), p. 19
  • "A further reason for underestimation of CFR may be that patients die before admission to medical services and therefore stay unconsidered in CFR figures of hospitals statistics." Moebus and Boedeker 2017 (preprint), p. 19
  • See Moebus and Boedeker 2017 (preprint), table 1, pp. 9-12, for a list of studies.

• 82

  "Aluminium phosphide works by releasing phosphine gas when it gets wet. Someone attempting suicide using the 3g tablets would only need to open the container and swallow the tablet; the tablet may become wet in their esophagus and get stuck there, or it may reach their stomach before getting wet, releasing all of its phosphine gas into the stomach. One tablet can be lethal. This is a very quick process that allows little time for reflection.

  "It is more difficult to [die by] suicide using the aluminium phosphide powder. It is difficult to consume a powder on its own, so a person might mix it with water to form a paste (releasing some of the gas before it reaches the mouth) or apply it to food (releasing some of the gas in the mouth as the food is chewed). Thus, a lower dose of phosphine gas reaches the stomach, or the more complicated process gives individuals a chance to rethink their decision. Something similar is seen in Sri Lanka in the case of carbofuran, another powder. This pesticide is not as lethal as expected because individuals are not able to ingest as high of a dose as they would with a concentrated liquid or tablet.

  "People are still dying through ingestion of aluminium phosphide powder. In India, roughly a few hundred or thousand deaths per year are still attributed to aluminium phosphide even after the tablets have been banned, and Professor Eddleston believes thousands of these deaths are actually occurring. Still, deaths by aluminium phosphide have fallen by 80%, as reported by academic studies, since the ban of the tablets." GiveWell's non-verbatim summary of a conversation with CPSP, January 15, 2020, pp. 2-3

• 83

  "The case fatality ratios for aluminum phosphide and organophosphate poisonings declined since 2000 despite an increase in aluminum phosphide exposures. The decline in aluminum phosphide mortality may be due to limited availability of 3 gm tablets and improved intensive care." Murali et al. 2009, p. 35

  However, we view this as weak evidence. Murali et al. 2009 compares case fatality of aluminum phosphide between 1980-89 and 1990-2004. The ban on the three-gram tablet form of aluminum phosphide in India did not occur until 1998.

  • "The total number of deaths over these 15 years was 461 (16%), compared to the 1980 to 1989 period (30%). The change was mainly due to the change in CFR from ALP poisoning, which declined from 0.59 in 1980 to 1989 to 0.22 in 1990 to 2004 with the major decline being observed between 2000 and 2004, even though the incidence of poisoning did not decline (Fig. 3). One possible reason for the decline in ALP CFR could be governmental restrictions on the sale of 3-gm tablets (initiated in late 1998) and it being available mainly as granulated powder in 10 gm plastic sachets. A second reason for the decline could be improved intensive care in our hospital. The mortality due to anticholinesterases in our hospital has also declined significantly, mainly due to improved availability of ventilatory care (Fig. 4)." Murali et al. 2009, p. 38

• 84

  See this spreadsheet, row 16.

• 85
  • "After Yavatmal (a city in eastern Maharashtra) experienced an epidemic of occupational pesticide deaths in 2016, Maharashtra's Chief Medical Advisor approached CPSP with a request for assistance. Following this request, CPSP signed an official memorandum of understanding with the Maharashtrian state government to help improve management of pesticide poisoning. Specifically, CPSP is compiling data on pesticide suicides in Maharashtra, which will be reformatted and presented to the government to inform decisions on pesticide regulation. It hopes to employ an individual directly in Mumbai to conduct this work." GiveWell's non-verbatim summary of a conversation with Professor Michael Eddleston, June 19, 2019, p. 4
  • "The government of Andhra Pradesh, an Indian state east of Maharashtra with a population of 50 million, is implementing a Zero Budget Natural Farming (ZBNF) strategy which encourages farmers to stop using pesticides. This was not a result of CPSP's work or driven by the high suicide prevalence in the state. However, if many farmers adopt this strategy, it could have a significant effect on pesticide-related death. CPSP is still uncertain whether ZBNF will be adopted widely in the state and whether reducing pesticide use in the state is a real possibility. ...

    "If wide use of ZBNF in Andhra Pradesh is confirmed, CPSP would like to quickly ensure a monitoring system is in place to reflect the strategy’s effect on health, suicide, and agricultural productivity. A colleague of CPSP at Harvard University, who works on sustainable agricultural systems and specifically pesticide-free agriculture, is seeking funding to review the general health effects of the ban. CPSP hopes to work alongside this researcher to collect and compare data reflecting the effect of reduction in pesticide use." GiveWell's non-verbatim summary of a conversation with CPSP, October 11, 2019, p. 2

  • "CPSP is continuing to await approval from the Indian Council of Medical Research (ICMR), which it must receive before it is able to initiate data collection in India." GiveWell's non-verbatim summary of a conversation with Professor Michael Eddleston, June 19, 2019, p. 4

• 86

  "A few years ago, non-governmental organizations (NGOs) presented India's government with a list of ~100 pesticides to ban, on the basis of being banned elsewhere. This followed an Anupam Verma report in 2016, which reviewed 66 pesticides and recommended banning eighteen of them. However, these bans were not completed until recently. CPSP submitted a document to the governmental committee chaired by Malhotra in India to explain the benefits of banning HHPs for preventing suicides (in addition to the other, already-acknowledged benefits for the environment and health). Dr. Utyasheva led CPSP's work on this document.

  "Twelve pesticides were banned by the government in 2018, and an additional 6 are scheduled to be banned in late 2020. CPSP expects to see a reduction in pesticide suicide as a result of these bans, as they include five HHPs that play a large role in pesticide suicide in India: methyl parathion, phorate, phosphamidon, dichlorvos, and triazophos. There are now only three or four remaining pesticides that CPSP believes are particularly important to ban in India, including monocrotophos.

  "Because CPSP was asked by civil society groups to present evidence to inform the committee's decisions, and those decisions were made shortly after CPSP's contributions, CPSP believes that its work contributed to the deliberations of the committee and consequently to the adopted decisions." GiveWell's non-verbatim summary of a conversation with CPSP, January 15, 2020, pp.3-4