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Pure Earth – Comprehensive Summary

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Last updated: December, 2024

Problem

There are nearly a billion children in the world with clearly unsafe levels of lead in their blood. Lead is a toxic metal that can impair cognition and physical health, and increase the risk of personality disorders and criminal behavior. In turn, these effects can all lead to lower wellbeing over the lifetime.

Lead exposure is associated with a similar health burden as HIV/AIDS and malaria, yet receives less than 1% as much funding, making it an extremely underfunded problem.

Organisation

Pure Earth was founded in 1999 and aims to address lead and mercury poisoning and pollution. Since their inception they have worked at around 3,000 locations in about 50 countries, primarily focussing on low- and middle-income countries (LMICs).

Intervention

In this work we evaluated Pure Earth’s programme to reduce lead exposure from cosmetics in Ghana. Chilo is a popular type of eyeliner in Ghana that is applied to both girls and boys, even at a very young age. Chilo has been found to have very high levels of lead in it, which can lead to increased blood lead levels.

To address the problem of lead in Chilo, Pure Earth’s programme will:

  • Advocate to the government and collect data to help target and neutralise the source of the lead in cosmetics with regulations and enforcement.

  • Provide technical assistance to ensure new regulations are followed and enforced.

Evaluation

Methods

Ideally, we would base our analysis on causal studies that show the long-term impact on wellbeing from Pure Earth intervening in an area. This evidence does not exist, so instead we estimate the effect indirectly by combining three sources of evidence:

First, we estimated the effect of reducing lead exposure on long-term wellbeing using 3 correlational studies on the general link between blood lead levels and wellbeing  (N = 1,157).

Next, we estimated the contribution of cosmetics to total lead exposure in Ghana, finding they account for 6.6% of blood lead levels. This is based on Pure Earth’s ongoing data collection and modelling of lead exposure.

Finally, we predict how much Pure Earth will reduce this exposure, using Pure Earth’s track record from similar projects and a best guess about how much earlier these changes will happen as a result of Pure Earth’s advocacy.

We then estimate the overall wellbeing effect of the whole project by multiplying the adjusted per person effect by the total population of those in Ghana under 10.

Impact

We estimate that the cosmetics programme has an overall effect of 0.025 WELLBYs per child (this includes the effect on the child and household spillovers). Therefore total WELLBYs produced is 0.025 WELLBYs * 9,162,721 children = 226,702 WELLBYs.

Cost

Based on Pure Earth’s forecasted costs, we estimate this programme will cost $2,093,235.

Cost-effectiveness

The cost-effectiveness of this program by Pure Earth is $9.23 per WELLBY. This means that for every $1,000 donated, the organisation creates 108 WELLBYs.

Quality of evidence

Our quality of evidence assessment is stringent. We assess quality of evidence according to an adapted version of the ‘GRADE’ criteria, a widely-used and rigorous tool for assessing evidence quality across healthcare and research fields. The GRADE criteria for evidence quality are very stringent, so we expect very few interventions that we evaluate for wellbeing in LMICs (which tend to be less well-studied) will score more than ‘moderate’ on the quality of their evidence. Considering most decisions about charities are made with little-to-no evidence, this is a substantial improvement.

Overall, we assess the quality of evidence is ‘low’, making our evaluation speculative. This is because:

  • The data on the effect of lead exposure on children on adult wellbeing is correlational, which is much weaker than casual evidence.

  • Our estimate of the percentage of total lead exposure attributable to cosmetics in Ghana is in part based on some guesses from experts.

  • Pure Earth is currently undergoing consulting with Rethink Priorities to improve their method of estimating this. We look forward to seeing the results of this work.

  • We are unsure what the counterfactual is.

  • In other words, we are unsure when the Ghanaian government would have introduced regulations to remove lead from cosmetics without Pure Earth’s help. This is a difficult figure to  estimate. Although we think we could improve our estimate, we do not expect there to ever be a really accurate way of forecasting this. We do think our estimate is extremely conservative though.

We do apply discounts to adjust the estimate downwards to account for these uncertainties. However we are particularly concerned about the first point because no discounts will ever be sufficient if lead has no causal effect on adult mental health. This is why we strongly encourage future research on lead to not only place an emphasis on ‘where is there lots of lead?’, but also ‘how much harm is it doing?’ and employ causal identification strategies, rather than rely on simple associations.

Depth of our analysis

We rate the depth of this analysis as low. We have only reviewed some of the relevant available evidence on the topic, and we have completed only some (~60%) of the analyses we think are useful. We’ve spent about 200 hours (or ~5 weeks of researcher time) in total on this analysis.

Funding need

As of writing Pure Earth has not secured any funding for this project yet, so the funding gap is the whole $1.8million.

Conclusion

  • This is the most cost-effective intervention we have evaluated to date, despite some conservative assumptions in our estimate. With more evidence we might be able to relax some of these conservative assumptions and cost-effectiveness could rise even higher.

  • However, this analysis is largely speculative, relying on limited evidence and assumptions.

  • We think research on most of our key areas of uncertainty is both feasible and likely forthcoming in the near future in most of these areas of uncertainty. Having said that, we would still encourage more researchers to assist in building the evidence base of this exciting relatively untouched area.

  • Until better data emerges, Pure Earth presents a potential “high risk, high return” opportunity for philanthropic funding.  

Our reports so far

In 2022 we performed a shallow exploration of reducing lead exposure as a cause area. We concluded that interventions to reduce lead exposure would probably hold cost-effective opportunities for improving wellbeing.

In November 2024, we published a cost-effectiveness analysis of Pure Earth’s cosmetic programme in Ghana.