Thinking at the Margin: Giving Where the Next Euro Does the Most Good
Every euro donated does not have the same effect. A charity can be extremely effective today but less so tomorrow once its most urgent needs are covered. This dynamic logic helps make donations more useful, without giving more, simply by giving better.
In philanthropy as in economics, diminishing returns are real. The first donations fill the most urgent gaps and generate the highest impact. As funding increases, each additional euro tends to yield slightly less benefit. That does not mean we should stop giving. It means we should ask when one cause becomes well funded enough that another becomes the better opportunity.
The Funding Gap: How Much More an Organization Can Achieve
The funding gap represents how much additional money an organization can effectively use to increase its impact. In other words: “If we added one more euro, what could it accomplish?”
A charity may have a great track record but a small funding gap if its current programs are already fully financed. Conversely, another organization, perhaps smaller or lesser-known, may have a large funding gap because it has programs ready to launch as soon as new funds arrive.
That is why Mieux Donner looks not only for the most effective charities overall but also for those with a significant remaining funding gap.
Examples of Funding Gaps
| Organization | Funding Gap | Expected Impact |
|---|---|---|
| Against Malaria Foundation (AMF) | ≈ $452M over 12 months | 88M nets distributed, 158M people protected |
| Clean Air Task Force (CATF) | €12.5M over 3 years | Hot rock geothermal program, expansion in Africa and the Middle East, +10M tCO₂ avoided |
Sources: Against Malaria Foundation – Funding Gap, Giving Green – Detailed Report on CATF, p.17, How we calculate the impact of carbon reduction.
AMF Today, Others Tomorrow: A Dynamic Approach
The effectiveness of a donation evolves over time. Mieux Donner regularly updates its recommendations based on how well each organization can use additional funds. This reasoning does not pit charities against each other. It aims to help as many people as possible.
Many organizations share the same mission to save lives and reduce suffering, but they differ greatly in effectiveness. By supporting those that currently offer the best cost-effectiveness ratio, we can achieve up to 100× more impact with the same resources.
Right now, Mieux Donner enables people to support several of the world’s most effective organizations in health and poverty reduction: Against Malaria Foundation (AMF), Helen Keller International (HKI), and New Incentives. These organizations are highly effective and still have substantial funding gaps.
The effective giving ecosystem depends on a balance between measurable short-term impact and long-term investment in new solutions. Some actors focus on exploration, while others, like GiveWell, combine both through their programs:
- Top Charities: proven, high-impact interventions.
- All Grants Fund: exploratory projects and emerging organizations.
Supporting today’s most effective organizations also strengthens this balance. Each euro donated to AMF allows GiveWell to allocate more research funds toward discovering the next high-impact opportunities.
If only 0.1% of the French population took the Giving Pledge to donate 10% of their income, millions more lives could be improved, and more resources could be dedicated to innovation for the future of giving.
What This Means for Your Donations
Thinking at the margin means adopting a new mindset about giving. Instead of asking “Which cause matters most?”, ask “Where will my next euro do the most good today?”
Even a small donation can have measurable impact if directed effectively. Effectiveness depends less on the amount and more on the direction of your generosity.
This collective, evidence-based approach turns generosity into a real force for measurable change. Each person who gives contributes to a coordinated effort to maximize global impact.