Hide table of contents

Written by Lucius Caviola & Joshua Greene

14 Months ago we launched Giving Multiplier to test a new technique for broadening the appeal of effective giving. This post gives a summary of the key results and insights. In short, we fundraised $1.5 million from about 3,500 donations, with most of the funds going to highly effective charities and coming from donors who are new to EA.


Giving Multiplier tests and deploys a technique for encouraging ordinary donors to support effective charities. It’s part of an academic research project. In our preprint paper we report on our studies in more detail.

Previous research has found that it is hard to encourage typical donors to support effective charities. Donors typically prefer to support charities they find personally/emotionally meaningful, even when they know that other charities are more effective. In many studies we (and others) have found that brief interventions based on arguments have little to no impact on most people’s attitudes and behavior. Here, our strategy is to work with people’s preferences (in a transparent way) instead of trying to displace them.

Giving Multiplier uses two techniques. The first is donation bundling: allowing donors to split their donation between their personal favorite charity — any legally recognized charity in the US — and a highly effective charity recommended by experts. In our experiments, we find that about half of participants (US citizens) are willing to split their donation 50/50 between their favorite charity and an unfamiliar highly effective charity. In Study 1 we found that offering a bundling option increases total donations to the effective charity by 76%, compared to only offering donors an all-or-nothing choice between the personal favorite charity and the highly effective charity. Study 2 shows that highly effective charities are especially appealing complements to personal favorite charities when splitting donations.

Subsequent studies show that bundling works because it allows donors to satisfy two competing motivations at the same time, to give with both the “heart” and “head”. Donors primarily want to support their favorite charity, but this preference is relatively scope insensitive (Study 3). Giving $100 to your favorite charity doesn’t feel twice as good as giving $50. This makes room for satisfying the secondary desire to give effectively. By making a split donation, donors get nearly all the satisfaction of giving everything to their personal favorite charity, plus the additional and distinct satisfaction of doing something highly effective (Study 4). Consistent with this, we find that bundle donors are seen as both highly warm and highly competent (Study 5). 

The second technique Giving Multiplier uses is a form of donation matching. Donors can get their donations matched at increasing rates for allocating greater proportions to the effective charity. In Study 6 we found that this technique boosts effective donations by an additional 55%. The matching funds are provided by a subset of donors who are willing to support the matching system, a technique we call micro-matching. Study 7 indicated that micro-matching could make the entire donation system financially self-sustaining.


We launched the website in November 2020. The project was funded by a $27,000 EA Funds grant (which did not pay for any of Josh’s or Lucius’ salaries).

We primarily advertised the website through unpaid media coverage and podcast appearances. This included articles in the LA Times, Project Syndicate, MarketWatch, and Vox.com along with podcast appearances on Waking Up (Sam Harris), Happiness Lab (Laurie Santos), and Mindscape (Sean Carroll). We also introduced a recruit-a-friend system that allowed donors (including all GWWC members) to invite their friends and family members to try effective giving through Giving Multiplier.

A note on matching: On our transparency page, we explain in detail how the matching system works. In contrast to conventional matching systems, ours allows donors to have an additional counterfactual impact in two ways. The first is through influencing which specific charities receive matching funds. The second is by participating in a supply-demand cycle in which the taking of matching funds encourages the provision of further matching funds, which then encourages further counterfactual donations. Since the added impact may be different from what donors would at first think, we require them to explicitly indicate that they’ve understood these considerations before they donate.


Since our launch in late 2020, we have fundraised a total of $1.55 million from 3,500 donations. Of this amount, over $1 million has gone to our recommended effective charities (about $820,000 is estimated to be counterfactual based on donors’ responses). See here for more detailed numbers: https://givingmultiplier.org/impact. (Once our academic paper is published, we may publish more detailed statistics.)

Our donations came from over 2,200 unique donors (some people make multiple donations). Most of the donors are new to EA. 73% indicated that they did not know about the effective charity they supported. The reception has been very positive. We have received hundreds of positive messages from donors.

38% of donors contributed fully or partially into the matching system, making the system self-sustaining. That is, we didn’t use any external funding to cover the required matching costs. With our current matching rates (which are increased relative to our previous rates), we estimate that a donor who supports the matching system can expect to have a positive return rate of about 50% (factor 1.5) in terms of counterfactual donations to effective charities. (This is calculated by dividing the mean counterfactual amount to effective charities by the mean amount of matching required. See also Study 6 for an experimental approach to estimate this number.)

We have noticed big differences in receptivity across audiences of potential donors. As noted above, our most successful podcast promotions were with Happiness Lab, Waking Up, and Mindscape. By contrast, we’ve received very few donations via Reddit and Twitter, despite many thousands of likes, upvotes and website visits. Our experience indicates that some audiences, in particular altruistically minded people with an interest in science, are orders of magnitude more receptive than others. These observations merit further study in controlled experiments. 

Last year, Giving Multiplier received an award from IDEO and the Bill & Melinda Gates Foundation for being an innovative concept in the digital giving space.


The appeal of effective giving may be broader than previously thought. However, most people don’t want to give up completely on causes that they value for reasons unrelated to impact. Renouncing traditional giving, which tends to be about feelings of personal connection, is highly unappealing to most people. Effective altruism often proceeds on the assumption (at least implicitly) that the embrace of effective giving requires the renunciation of traditional giving. And at the level of a given monetary unit that’s true: If you give a dollar ineffectively, you can’t give it effectively. But it’s not entirely true at the level of individual donors, or even at the level of a single donation transaction: by splitting their donations, donors can get the psychological benefits from both effective giving and traditional giving. And our studies show that this simple strategy can substantially boost effective giving in typical donors.

The share of the population that is willing to give effectively, despite not being primarily focused on effectiveness when giving, may be very large. In our studies of the general population, every second person was willing to split their own donation 50/50 between their favorite charity and an unfamiliar highly effective charity. (And that’s without matching funds.) This suggests that this approach could scale by multiple orders of magnitude with the right kind of marketing, yielding an extremely large return.

We wish to be clear, however, that we are not claiming that the evidence presented warrants a general shift in EA’s marketing approach. EA has been enormously successful at attracting financial support using familiar arguments urging donors to fully optimize their giving for impact. For early adopters and those with a similar mindset, the classic approach may be the best approach. And, of course, we ourselves were drawn into EA by these classic arguments. Nevertheless, the globally best approach may be to have more than one approach. It’s possible that the outreach strategy applied by Giving Multiplier can broaden the circle of effective giving without crowding out or otherwise undermining the standard EA outreach strategy. In other words, we view Giving Multiplier’s approach as a complement to, and not a replacement for, the standard EA outreach approach.

Many people are receptive to EA ideals but know little about EA and approach it with some reluctance due to competing priorities. We believe that donation bundling offers an easy on-ramp for EA newcomers and sympathizers. Some Giving Multiplier users, we hope, will get more engaged and ultimately become active effective altruists. For these reasons, we intend to keep the website running. It works, needs little maintenance, and is expected to continue raising funds for highly effective charities and introducing people to effective giving.


We are grateful to many people who have helped us make Giving Multiplier possible. This includes Fabio Kuhn for developing the website and Daniel Rüthemann for designing it; Mark Ulrich, Tina Roh, Santi Hernandez and the team at Every.org; Peter Singer, Charlie Bresler and the team at The Life You Can Save; Luke Freeman and the team at Giving What We Can; Jim Bobowski, Buddy Shah, and the team at GiveWell; Benjamin Lipinski, Marta Krzeminska, Chris Lloyd, Joe Brownrigg, Marka Ellertson, Emma Gray-Starcevic, Vaidehi Agarwalla, Kate Yuan for marketing advice; Ari Kagan, Nick Fitz and the team at Momentum; Sam Harris and Will MacAskill; Duncan Peacock and the TED Mystery Experiment; Laurie Santos and the team at the Happiness Lab Podcast; Sean Carroll and the team at the Mindscape Podcast; Stefan Schubert, Joshua Lewis and Fiery Cushman for providing feedback on our manuscript; EA Funds; and many others.

Sorted by Click to highlight new comments since:

Pretty cool that you're running all these studies!

Speaking loosely*, it feels like >70% of the psychology academics I know who's interested in effective altruism are studying some version or another of "psychology of effective vs ineffective givers for small donations." And yet I very rarely (never?) talk to non-psychology researchers or decision-makers in EA who think that this is an unusually promising/impactful/decision-relevant avenue of inquiry. 

I'm curious whether you a) agree with these impressions, b) have strong views on why this disconnect exists and c) have object-level viewpoints you'd like to share about why questions in this general line of inquiry should/should not be prioritized (whether for direct impact or other reasons).

*Just personal impressions, not a survey or anything.

Thanks, Linch.

First, you’re right that several EA psychology researchers are studying how people donate to charity. But most of them (including myself) are also studying other EA-related topics, such as the psychology of xrisk and longtermism, moral attitudes towards animals, etc. My hunch is that only a minority of currently ongoing EA psychological research projects have charitable giving as their primary topic of interest.

Second, as David pointed out, donation choices are a useful behavioral outcome measure when studying the public’s beliefs, attitudes and preferences about EA related issues more generally. In many cases, the goal of the research is not necessarily to understand how people donate to charity specifically but to understand the fundamental psychological drivers of and obstacles to EA-aligned attitudes and behavior more generally (example). Studying these in the context of charitable giving is an obvious and often straightforward first step — in the hope that these insights can be generalized.

For example, the fact that people are willing to split their donation, as described in the post, tells us something more fundamental about people’s preferences structure (the fact that most people value effectiveness but only as a secondary preference), the potential market size of EA in the general public, and possible routes for reaching a wider adoption of EA ideas. Another example is the study of individual differences: who are the people who immediately find EA ideas appealing, where can we find them and how should we target them? It’s natural to test this, in part, by observing people’s donation choices.

My view on prioritization is that psychological research can be useful when it yields such fundamental insights. But there can also be really useful applied research, such as marketing or psychometric research that can be practically useful for recruitment.

My view on prioritization is that psychological research can be useful when it yields such fundamental insights. But there can also be really useful applied research, such as marketing or psychometric research that can be practically useful for recruitment.

Can you elaborate a bit more on what you consider the distinction between fundamental and applied research is, here? (To be clear I'm aware of the usual distinction, I'm just  confused about how it's applicable here).

Linch, fwiw I try to consider this case here ... see fold "Why should ‘Effective Altruists’ and those interested in long-term global priorities care" , and in some other writings I could share with you. But I'd also be interested in Lucius' take

Also, I think Linch, in my impression

  • you might be overstating the extent to which the EA-interested psych people are doing this; perhaps my connection to you has made this more salient?

  • also, as I argue in the link etc., the 'small donations' (or even better, modest real-world donations) are not always/only the outcome of interest itself, but these are pretty good measures of actual commitments, beliefs and preferences (economists tend to be pretty favorable to this too) ... In contrast self-stated attitudes, hypothetical choices, or retrospective 'why did I make this choice' can be unreliable.

This is really cool - thanks for sharing.

Do you think this project is something that could be scaled up by being funded with more EA capital?

Have you done anything to try to get your audience more brutally engaged with EA in more than just donating to a charity they haven’t really heard about?


Perhaps, but we are uncertain. It depends on whether we can find a scalable strategy for reaching donors who are amenable to EA but not yet engaged with effective altruism. Such a strategy might come from paid advertising, further earned media coverage (our strategy so far), or from the formation of institutional relationships (e.g. with businesses, universities, or wealth managers) who offer guidance or incentives for charitable giving.

Yes, we've recently introduced our donors to GWWC. (Results of that campaign are not in yet.)

Congratulations Lucius, these are pretty amazing results. I am quite surprised that on the extensive margin 38% of people contributed to the matching system. What were your priors about contributions and did this also surprise you? 

Yes, it was initially quite surprising that so many donors are willing to support the matching system. We found similar results when we tested it with MTurk participants (who were given a small bonus which they could give or keep; see Study 7). One possibility is that it's a kind of intergenerational reciprocity tendency, where people who benefited from the generosity of previous donors want to pay it forward to the next ones.

Interesting. I wonder if the mechanism is similar to making a donation when there is matching. As in, people think they are giving more money to the cause because their donation is 'doubled'.  By providing matching funds they might believe they are going to bring more money in. Alternatively, if they see GM as a public good itself (and like this idea), they have some preference to fund it for that sake. 

Would love to know more about this! 

Great write-up! The "many people are happy to donate to effective charities as long as they also donate to their favorite charity" point did indeed come as a surprise. Seems like a very valuable insight for certain types of outreach. 

I've given a number of small talks about effective donations to various non-EA audiences. In the end -- after having made my case for focusing on effectiveness in giving -- I encouraged them and said: "If my argument convinced you, how about making a start and using half of your next batch of donations for the most effective charities."

Do you see any problem in taking your research as evidence that this might be sensible advice? I know Giving Multiplier does something different. However, I wonder whether it's similar enough to be transferable?

Thank you, Lucius. I've added Giving Multiplier to my list of charities to donate each year. 


GiveDirectly - lifting people out of poverty, 2.6X economic multiplier/RCT research into UBI 

Helen Keller International - lowest cost way to save a young child 

Clean Air Task Force- lowest cost way to offset carbon emissions ($1.26 per ton)

Giving Multiplier - 1.5X effective multiplier to most effective charity/multiply the number of effective altruists 

Local Food Bank meal donations (my personal passion project since I went hungry for three months). 

This year will be a record year of income for me, so I'm making it a record year for giving. 

Exponentially giving more each year until I not just surpass 50% of my income but hit 5% of my net worth, which, thanks to my family's hedge fund, will take me many times above my income. 

My two greatest passions and skills in life are making and giving away lots of money;) EA has given my quest for billions an actual meaning. Thank you to you, GiveWell, Founders Pledge, Peter Singer, William MacAskill, and all the other people who have made it easy for people like me to earn, invest, and give with meaning and maximum effect. 

I now have a spreadsheet that counts my annual and cumulative inflation-adjusted donations, meals donated, lives saved, people lifted out of poverty, and economic impact. 

For math and evidence-based spreadsheet nerds like me, EA combined with patient philanthropy is a match made in heaven:)

My dream is to beat Andrew Carnegie's philanthropy record of $438 billion in inflation-adjusted giving. 

My hedge fund will turn into a permanent philanthropic trust which will let me eventually donate $1 trillion (adjusted for inflation) over the next few centuries. 

Give thousands and you can make a difference to some. 

Give millions and you can change a lot of lives. 

Give billions and you can change the world. 

Give trillions and you can change everything. 

Curated and popular this week
Relevant opportunities