Counting (some of) our impact so far

Our Headline Impact (2022–2025)

• Money influenced: $10.5m
• WELLBYs created (best-guess estimate): 252,451
• Years of depression avoided: 194,193 years
• HLI’s total costs: $2.7mil
• HLI’s overall cost per wellbeing-year (WELLBY): $10.73
• HLI’s overall cost per year of depression-equivalent averted (YoDA): $13.95
• HLI’s WELLBYs per $1k: 93.2

The rest of this page provides a brief explanation of how we calculated these numbers, what they mean, and what they exclude.

Context

In HLI, we conduct research to find the best ways globally to improve human happiness. A primary audience for this are donors who are looking to do the most good with their donations.

The work that follows considers the narrowest, most countable part of our impact: where we know we have influenced donors to give to different charities, and the additional impact this has had. It necessarily discounts any wider impacts of our work, such as influencing researchers or policymakers, or where we can't track the donations moved.

Specifically, here we assess our money-influenced from 2022 to 2025. HLI started in 2019, and we have a significant 'R&D' phase developing the wellbeing methodology and assessing the cost-effectiveness of charities, and started making recommendations in 2022. In 2024, we published the first global comparisons of charities in the World Happiness Report. We are now working to scale up our money influenced, and expect the total moved to go up sharply, and thus for our own cost-effectiveness to also substantially increase.

We have written this overview of our impact because we think it’s important to count what we can to keep ourselves accountable and transparent. 

In the following text we will assume knowledge of what a WELLBY is. If you don’t know what the WELLBY is then check out our explainer page.

How We Calculated Our Impact

Our impact is the difference between the world as it is today, and what it would have been had HLI not existed. This world in which HLI did not exist is called the ‘counterfactual’, and thus the impact viewed this way we referred to as our ‘counterfactual impact’.

HLI's most countable counterfactual impact comes from improving the quality of allocation among donors who were already going to give effectively — by identifying better charities than those available before our work. We also bring in some donors new to effective giving by offering options aligned with their values (improving lives rather than saving them), or covering cause areas that weren’t really covered (mental health) but we conservatively assume they’d all have given effectively anyway. The method here is the same as what we set out in our 2025 Annual Report (p 22).

Our simplifying assumption is that, without HLI, donors would have given to the best life-improving charities available before our work i.e., GiveDirectly (which provides cash transfer) and deworming charities. Since our 2022 deworming report found no clear wellbeing effects of deworming, we use GiveDirectly alone as our baseline — a conservative choice that works against us.

For each charity HLI has influenced funding toward, we calculate the difference in WELLBYs per dollar between that charity and GiveDirectly, then multiply by total funds moved. The modal case is a donation to StrongMinds (40.4 WELLBYs/$1,000) rather than GiveDirectly (7.55 WELLBYs/$1,000), an uplift of 32.85 WELLBYs per $1,000. Note that if we concluded the donors would have given nothing, the counterfactual here would just be 40.4 WELLBYs/$1,000, a ~25% increase. So, in our analysis, the conservative assumption the donors would have given to an effective charity (GiveDirectly) doesn’t make much difference. We see this as fitting with the accepted view that it really matters to find and support the best charities.

Money influenced

This section details the money we are confident we influenced towards high-impact charities as a result of our work. This is an imperfect exercise which is limited by what we are about to count. For this, we look at:

1. Direct donations processed via HLI (i.e. money sent to us we then send to charities).
2. Direct donations reported by charities (i.e. money charities receive where the donors cited HLI’s work as influential).
3. Donations reported by partners (i.e. organisations that use HLI’s recommendations and either allocate their own funds to them, or advise others who do so).

We then report:

4. A combined total from the 3 paths above.

These streams are mutually exclusive (we avoid double counting) but not jointly exhaustive. We are not able to capture the wider influence of our work. For instance if donors give based on our recommendations, but they do not give through us, a partner, or report giving based on our work, then we do not know about this and have to assume zero impact.

Results: HLI’s cost-effectiveness

Looking across HLI's full history , we calculate 252,451 additional WELLBYs generated on total costs of $2.71m — approximately 93 WELLBYs per $1,000 spent (costs are from 2019 to 2025, and money moved figures from 2022 - when we started making recommendations - to end of 2025)

Perhaps the more intuitive way to put this is as follows. It turns out that 1.3 WELLBYs are equivalent to not having depression for a year. So we also present our cost-effectiveness in ‘YoDAs’ (Year of depression-equivalent averted). On this, the average cost for HLI to prevent a YoDA is $14. What that means for previous donors is that, for each $14 you gave to HLI’s budget, the average impact, looking back, is that you prevented the equivalent to a year's depression for 1 person for 1 year.  As a potentially helpful analogy: if we think that 60 years of depression would be a ‘lifetime of suffering’, then we could say that it has cost $827 for HLI to ‘save a life from suffering’.

As further comparisons, these figures of 94 WELLBYs/$1,000 and $14 per YoDA mean funding HLI turns out to have been 12.5x more cost-effective than supporting best charity life-improving charity we expect donors would have funded prior to HLI’s work, namely GiveDirectly. In other words, if you were wondering in 2019 whether to donate to cash transfers or HLI, these numbers suggest you would have had 12.5x the impact by giving to HLI. We think this shows the value of research to determine the priorities, followed by efforts to communicate it. Importantly, we wouldn’t have WELLBY estimates for any of these charities without HLI’s work.

For 2025 specifically: we generated 69,487 WELLBYs at a cost of $525,201 — 132 WELLBYs per $1,000, or $9.83 to avert a year of depression. This is just over 3x more effective than our Top Charity, StrongMinds, who create 40 WELLBYs per $1000 donated.

What does this miss?

1) Paradigm shifting effects

We see our impact as an organisation as coming through two paths. The first is finding and moving philanthropic resources towards the most cost-effective ways to improve wellbeing. As seen above, we assess this via the counterfactual impact of our money influenced.

The second is causing a paradigm-shift among decision-makers in philanthropy, policymaking and academia so that these actors take happiness seriously and use wellbeing data to set their priorities — even if they are not trying to maximise the impartial good. This is harder to quantify and we track indicators like engagement with HLI and its work, though do not include it in our calculated counterfactual impact.

These paths are connected: as the first team to attempt wellbeing cost-effectiveness, our methods and findings serve as proof of concept that others can adopt to improve human wellbeing.

2) Missed donations

Given we only launched direct giving through our website at the end of 2024, much of our impact has been channelled indirectly through partner organisations and donors who use our research and charity recommendations but give donations directly to the charities. Although we believe we have identified most of the donations made indirectly through these partner organisations, we are also sure there are donations that we have failed to track. Thus we treat our estimated money influenced number as a lower bound.

3) Redirected donations

It is hard to quantify our impact as a challenger in the charity evaluation space. For example, our replication of GiveWell’s deworming analysis won their “Change Our Mind” competition, and resulted in them redirecting between $2 and $8million in funding away from deworming.

Another more recent example of the influence of our work redirecting donations is a philosophical paper on moral uncertainty written by our Director, Dr. Michael Plant, which is being used in Rethink Priorities’ donation allocation tool.

However, in both cases, working out where the money redirected was spent instead, and thus the wellbeing created, is a challenging and time consuming piece of work, so we have not included it in our counterfactual impact estimate.

Conclusion

Even during a period in which research rather than fundraising was our primary focus, HLI and our donors have helped generate wellbeing equivalent to 194,000 years of depression avoided. As we transition into our 2025–2030 scale phase, we expect both money moved and wellbeing created to grow significantly. The methodological foundation is now in place; the next step is to bring these tools to scale. If you want to be part of the next step then sign up to our mailing list, or donate now.

Versions

Download the different versions of this page:

• 2025/11/21

More information

For more information please check out our annual review below:

• 2020 Annual review
• 2021 Annual review
• 2022-2023 Annual review
• 2024 Annual review
• 2025 Annual review