Giving well
How to Leave a Charitable Bequest That Does the Most Good
Some charities do dozens of times more good per dollar than others. Here's how to choose a cause, find high-impact programs, and write a bequest that stays effective for decades.
Short answer
Pick the cause you care about, then direct your gift to programs with strong evidence and a low cost per result. Because bequests often arrive years after a will is signed, it's safest to lock in the cause rather than a single charity, and let a research-guided fund or your executor choose the best organizations when the gift arrives.
Why does impact per dollar vary so much?
Charities working on the same problem can differ enormously in what a dollar buys. When philosopher Toby Ord analyzed 108 health interventions from the second edition of Disease Control Priorities, results ranged from 0.02 to 300 years of healthy life (DALYs) per $1,000. The best intervention was about 60 times as cost-effective as the median, and about 15,000 times as cost-effective as the worst (Giving What We Can).
Large differences show up in other causes too:
| Cause | What evaluators measure | A recent finding |
|---|---|---|
| Global health | Cost per life saved | GiveWell estimates its four top charities save a life for roughly $3,500 to $5,500 in donations (GiveWell) |
| Education | Learning gained | A review of 96 randomized trials found tutoring raised achievement by 0.37 standard deviations on average (NBER) |
| Animal welfare | Animals helped per dollar | Corporate cage-free and broiler campaigns affected an estimated 9 to 120 years of chicken life per dollar (Rethink Priorities) |
| Rare disease | Treatments unlocked | The Cystic Fibrosis Foundation invested about $150 million in drug research, then sold its royalty rights for $3.3 billion (Scientific American) |
These are estimates, and evaluators revise them often. The pattern holds, though: where your money goes matters as much as how much you give.
What should you ask before choosing a charity?
Independent evaluators use versions of the same framework. These are the seven questions we ask:
- Scale. How many people or animals does the problem affect, and how severely?
- Neglect. How much money already flows to it? An extra dollar matters most where funding is thin.
- Evidence. Has the approach been tested, ideally in randomized trials, or proven by a long track record?
- Cost-effectiveness. What does one unit of good cost: a life saved, a year of healthy life, a year of learning?
- Counterfactual impact. Would the work happen anyway without your gift?
- Room for more funding. Can the organization put more money to good use right now?
- Durability. Will this still be a good use of money when your gift actually arrives?
You don't have to answer all seven yourself. GiveWell, Animal Charity Evaluators, Giving Green and J-PAL publish their research for free.
Why do bequests need extra care?
A bequest is paid at death, often years after you sign. In a study of Australian probate records, charitable wills were signed an average of 5.6 years before death (James and Baker). In that time a charity can merge, close, change its mission, or be overtaken by something more effective.
That's why GiveWell advises against naming one of its specific top charities in a will. It suggests a gift that can be directed to the best opportunities at the time.
How do you keep a bequest effective for decades?
Three tools help:
- Lock the cause, not the charity. Give to a fund dedicated to a cause, or ask your executor to choose effective organizations within that cause. Your purpose stays fixed while the recipients can change.
- Add a substitute-charity clause. If a named charity no longer exists or can't accept the gift, your executor gives it to the organization whose work is closest.
- Give a percentage, not a dollar amount. A percentage of your residuary estate grows or shrinks with your estate, so your family's share stays protected.
If you'd like your name on it, a named legacy fund does all three. It holds your gift, follows your causes, and keeps giving for years or forever. See how to create a foundation in your will.
What does the wording look like?
Here's sample cause-based wording to discuss with your attorney:
I give ten percent (10%) of my residuary estate to one or more charitable organizations described in Sections 170(c) and 2055(a) of the Internal Revenue Code, selected by my Executor, to be used for improving health and reducing extreme poverty in low-income countries. I ask that my Executor consider the research of independent charity evaluators at the time of my death.
Our free builder writes this for each cause you choose, with your percentages filled in.
Frequently asked questions
Do I have to choose the most effective cause?
No. Most people give to causes with personal meaning, and that's the right place to start. Impact-per-dollar thinking helps most within the cause you choose, by finding the programs where your gift does the most.
Can I leave money to a charity evaluator's fund in my will?
Yes. GiveWell, Giving What We Can and The Life You Can Save all publish bequest wording on their websites. GiveWell receives bequests through its legal entity, The Clear Fund.
Isn't a large, well-known charity a safer choice?
Size isn't the same as impact. Well-known charities can be excellent, but the question for your gift is what one more dollar accomplishes there compared with elsewhere.
What if the evidence changes after I sign my will?
That's the advantage of cause-based gifts and research-guided funds. They're designed to follow the evidence as it changes, without you having to rewrite your will.
Sources
- Toby Ord, "The Moral Imperative toward Cost-Effectiveness in Global Health" (2013), via Giving What We Can
- GiveWell, "Top Charities" (updated September 2025)
- GiveWell, "Planned Giving"
- Nickow, Oreopoulos and Quan, "The Impressive Effects of Tutoring on PreK-12 Learning", NBER Working Paper 27476 (2020)
- Rethink Priorities, "Corporate campaigns affect 9 to 120 years of chicken life per dollar spent" (2019)
- Scientific American, "Cystic Fibrosis Charity Sells Drug Rights to Pharma for $3.3 Billion" (2014)
- Russell James and Christopher Baker, "The Timing of Final Charitable Bequest Decisions"
This article is general information, not legal, tax or financial advice. Laws vary by state and change over time. Talk with a licensed professional about your situation. First published October 24, 2026.