Most charity evaluation asks how many deaths or how much income a program buys. The Happier Lives Institute (HLI) asks a different question: how much happier does it make people, and for how long?
Its unit is the WELLBY, one point of life satisfaction on a 0-to-10 scale, for one person, for one year. Move someone from a 4 to a 6 for a year and you have produced two WELLBYs. Governments including the UK Treasury use a version of the measure in policy appraisal.
On that yardstick, HLI’s top picks are two mental health programs.
The programs
StrongMinds runs group interpersonal therapy for women with depression in Uganda and Zambia, delivered by trained lay counselors, not psychiatrists. HLI’s estimate: 40 WELLBYs per $1,000, or about $25 per WELLBY. StrongMinds reports its cost per person treated at about $45 (2023 spending).
Friendship Bench in Zimbabwe trains community health workers, often older women known as “grandmothers,” to deliver problem-solving therapy on a park bench outside clinics. HLI’s estimate: 49 WELLBYs per $1,000, about $21 per WELLBY.
HLI also lists as “promising” Pure Earth (lead exposure, about 105 WELLBYs per $1,000) and Taimaka (treatment of acute malnutrition in Nigeria, about 66 WELLBYs per $1,000), and gives honorable mentions to a crime-prevention therapy program (ACTRA), a school mental health program (Shamiri Institute) and parenting programs.
The 2025 World Happiness Report, to which HLI contributed a chapter, made the wider claim that $1,000 to a highly effective charity can produce the same wellbeing gain as $150,000 to an average one.
Where the dispute is
GiveWell, which funds programs by cost per death or income gain, reviewed HLI’s StrongMinds analysis and reached a much lower number. The disagreement is not about whether therapy helps. It is about three modeling choices:
- How big the effect is. HLI leans on published trials of group therapy, which tend to show large effects. GiveWell discounts those for publication bias and for the gap between trials run by researchers and programs run at scale, and its own read of StrongMinds’ routine data showed smaller improvements.
- How long it lasts. A therapy course is short. If the benefit fades in a year, WELLBYs are few. If it lasts several years, they multiply. HLI assumes a slower fade than GiveWell does.
- Spillovers to households. HLI counts some benefit to family members of the person treated. GiveWell counts less.
Depending on those choices, the same program comes out anywhere from “one of the best uses of money in the world” to “decent but below the bar.” HLI has revised its StrongMinds figure downward more than once as new data came in, which is what you want an evaluator to do.
How to think about it
- If you believe suffering matters directly and not only through death and income, the WELLBY approach is asking the right question, and mental health programs in poor countries look very cheap by that measure. Nothing in the rich world competes: a course of therapy in the US costs a hundred times what StrongMinds spends per person.
- The uncertainty band is wide. A reasonable donor should assume the true figure is somewhere between HLI’s and GiveWell’s, and that it is still likely to be competitive with good global health charities rather than far above them.
- Funding is not saturated. StrongMinds reported a roughly $3.3 million gap against its 2025 target and projected a $6.9 million gap for 2026. Friendship Bench is smaller and less studied.
Bottom line
Lay-delivered group therapy in East and Southern Africa is cheap, has real trial evidence, and treats a condition most charity money ignores. The headline “$25 per WELLBY” is the optimistic end of a live debate. Read it as “plausibly very good, not proven exceptional,” and it belongs on a shortlist.
Method notes
WELLBY figures are HLI’s, as listed on its recommendations page when we read it. We summarize the GiveWell critique from its published assessment; the three points above are our grouping, not GiveWell’s headings.
Sources
Figures come from the cited sources as of the dates shown. Cost-effectiveness estimates change as programs and evidence change; check the source before giving. We are not financial advisers and receive nothing from any charity named here.