Pure Earth
Pure Earth
Getting lead out of the eyeliner Ghanaian children wear, through advocacy for regulation and help to enforce it.
Click any figure to learn how we worked it out
Cost-effectiveness
The cost-effectiveness of this programme by Pure Earth is $9.49 per WELLBYOne WELLBY is equivalent to a 1-point increase on a 0-10 wellbeing scale for one year. Read more. This means that for every $1,000 donated, the organisation creates 105 WELLBYs.
Put another way, every $12 donated creates as much wellbeing as averting a year of depressionDepression is associated with about 1.3 points less life satisfaction, so averting a year of it is worth about 1.3 WELLBYs. Read more (a YODA) for someone. The YODA is a way of making WELLBYs concrete; it does not mean Pure Earth treats depression.
We calculate the cost-effectiveness by pairing the estimated effect for each charity with the estimated cost to deliver the intervention.
Impact
We estimate that the cosmetics programme has an overall effect of 0.0247 WELLBYs per child (this includes the effect on the child and household spilloversThe effects on other individuals, such as those in the household, who did not receive the intervention but may nonetheless benefit. Read more). Across the 9,162,721 children under 10 in Ghana, that is 226,702 WELLBYs in total.
How we arrived at it
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.
Cost
Based on Pure Earth’s forecasted costs, we estimate this programme will cost $2,150,302. Spread across the children it protects, that is $0.235 per child, which creates 0.0247 WELLBYs.
Funding need
$1.55M is how much Pure Earth could absorb right now for their cosmetics project in Ghana without it changing its cost-effectiveness. Every dollar of that gap buys roughly the same wellbeing as the last one did.
Note that Pure Earth runs several programmes and we just focused on this one, as they said it was their most cost-effective unfunded programme.
Quality of evidence: Low
Quality of evidence is about the world: how much the studies that exist can tell us about Pure Earth’s programme.
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. As a result, 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 as ‘low’, making our evaluation speculative. This is because:
- The data on the effect of children's lead exposure on adult wellbeing is correlational, which is much weaker than causal 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 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: Shallow
Depth of analysis is about our work: how much of the evidence we reviewed and how complete the analysis is.
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.
This was a shallow evaluation, but it is currently the deepest wellbeing-focused assessment of lead exposure we’ve produced. How we rate evidence and depth.
Why we recommend Pure Earth
We rate Pure Earth as a Promising Charity because their lead-removal work appears extremely cost-effective at improving global wellbeing, despite substantial uncertainty in the evidence base. 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. 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.
What Pure Earth does
Pure Earth works on lead and mercury pollution in low- and middle-income countries, and protected 1,200,000 people in 2024. We evaluated one programme: ending lead-contaminated cosmetics in Ghana, where chilo, an eyeliner applied to young children, can contain very high levels of lead. The project advocates for regulation, collects the data to target it, and helps see the new rules enforced. Read our interview with Pure Earth.
Our research about Pure Earth
- April 2023Lead exposure as a cause 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.
- November 2024Evaluating Pure Earth in Ghana We published a cost-effectiveness analysis of Pure Earth’s cosmetics programme in Ghana.
Frequently Asked Questions
Why isn’t the most cost-effective charity automatically a Top Charity?
We also weigh the quality of the evidence and the depth of our own review. When either is lower, we are less certain about the exact cost-effectiveness, and the estimate is more likely to move when new information arrives.
In our experience, cost-effectiveness estimates usually, though not always, go down under further scrutiny. Our Promising Charities have been analysed in less depth than the Top Charities, so we would expect their figures to fall somewhat on closer examination. We can’t point to the particular factors that would move them: if we could, we would already have adjusted the numbers.
Which recommended charities should I donate to?
If you are a donor who wants to be confident that your donation is making a real difference, we recommend donating to our Top Charities. We think our two Top Charities are roughly as cost-effective, so you might consider splitting your donation between them.
If you are comfortable with more risk and uncertainty but want to maximise the expected value of your donation, you might consider our Promising Charities. We think these are “higher risk, but potentially higher reward” options. If you want to donate to any of them, we recommend reading our full report so you are familiar with the uncertainties in our evaluation.
If you want to support all our recommended charities and HLI at the same time, you can donate to the Happier Lives Fund. 10% of your donation powers further happiness research, while 90% of your donation is disbursed quarterly to the charities with an allocation based on the latest available evidence to maximise overall impact.
Do WELLBYs undervalue systemic changes?
Some argue cost-effectiveness metrics focus too much on individuals rather than systemic transformation. Shouldn’t we be focusing on policy reforms, infrastructure, and changing the system that allowed us to get here in the first place rather than just treating the symptoms of these causes?
1. We do evaluate systemic changes!
Most simply, we already have evaluated systemic changes. For instance, we ran an evaluation of Pure Earth in November 2024, an advocacy charity aimed at changing government policies on lead pollution. We’ve also evaluated the benefits of immigration reform.
2. While we are open to systemic change, it is hard to evaluate
We prioritise issues which we think are:
- Important – it could massively improve wellbeing
- Tractable – it seems possible to solve and
- Neglected – there are not many resources already dedicated to this issue
While systemic changes are often important, it is their tractability and neglectedness which means they often rank lower on our priority list. In other words, systemic changes often are really hard, and already have a lot of money going into them.
Note that our evaluations of advocacy programmes will inherently carry more speculation due to the difficulties in calculating the counterfactual (i.e., it is hard to say when a policy would have otherwise passed), probability of success (how likely is this advocacy action going to succeed), and causal attribution (how much has this advocacy action really contributed to the success).
3. Individual interventions can drive grassroots systemic change.
We would challenge the separation between individual-level interventions and systemic change. They are often interwoven.
Empowering individuals can create grassroots momentum. Research shows that alleviating poverty and mental health struggles frees cognitive bandwidth, enabling people to push for broader reforms. For example, charities like StrongMinds and Friendship Bench work with the health ministries of their respective countries to improve access to mental health.
Do WELLBYs undervalue long-term changes?
First, it is important to note that a WELLBY is the integration of the wellbeing impact over time (i.e., wellbeing × years). WELLBYs are more than capable of capturing long-term benefits to individuals and we have already used them for this purpose.
This is about modelling the right thing, not about the WELLBY itself.
So, even for interventions that might seem short-term (e.g., psychotherapy and cash transfers), we have included long-term effects.
We have also modelled interventions with very long-term effects. For example, see our reports on parenting programmes that impact children well into adulthood or lead exposure reduction programmes that can alter childhood development and change people’s entire life paths.
Note that we don’t discount future WELLBYs. We value WELLBYs created in the future equally to present ones. If charities can show long-term benefits, we count them. We might reconsider this, if appropriate, but until now this is how we have operated.
Do you get money from the charities you recommend?
No.
We don’t take any money from charities for recommending them because this would remove our impartiality.
We exist because we want the world to be a happier place and, therefore, we think there should be a free, impartial source of information about which charities do the most for people’s happiness and wellbeing.
Is your question missing from this list? Contact us at hello@happierlivesinstitute.org.
Support the important work Pure Earth does
A donation here helps get lead out of the cosmetics young children in Ghana wear every day.