Dive into the Evidence

February 2021

The Better Giving Studio aims to bridge the gap between research and real world innovation by getting better products into the hands of everyday givers. Contained in this post are evidence citations that support the concepts on this site.


  • Asking people to donate a potential windfall before it is certain encourages generosity. In five lab and field experiments (n=1,363), charitable donations were solicited from small lottery winnings, varying in whether the outcome of the lottery was known at the time. Pooled together, participants were 23% more likely to commit to donate from the winning income and commit 25% more when asked to donate before the lottery’s outcome is determined, compared to those who were asked to donate after learning they had won. (Kellner et al., 2019)
  • A “year-end-review” of a donor’s holistic giving can promote generosity. In one field experiment, some donor-advised fund (DAF) clients received an end-of-year report highlighting their giving year-to-date including the dollars they had contributed to their DAF, dollars granted, number of grants issued, and more. Other clients received a standard email. The end-of-year report which was designed to prime clients’ philanthropic identities and impart a sense of agency boosted the proportion of clients who made a contribution to their account while increasing the amount contributed. (ideas42, 2020)


  • Mentioning another donor’s contribution level can increase donation amounts. In a field experiment at a public radio station (n = 538), some donors were given information about how much others had contributed. Fundraisers used the script, “We had another member; they contributed $300. How much would you like to pledge today?” Researchers found that sharing this information, compared to simply asking for a pledge amount, increased average donation amounts by 12% (Shang and Croson 2009).
  • Visible indicators of participation influence giving decisions. Researchers put a transparent donation box in a free art gallery and varied the contents of the box. In different trials, the box was filled with $100 in coins, small bills, large bills, a mix of currencies, or no money at all. Researchers then tracked contributions by visitors to the gallery (n = 21,259) and found that donation amounts tend to reflect the original contents of the box. Presenting many coins results in a large number of small contributions, and presenting a few larger bills results in a smaller number of contributions at higher amounts. Researchers conclude that people estimate whether and how much most others have given when making their own giving decisions. (Martin and Randal, 2008)
  • Donors react differently to charity efficiency information depending on the social-signalling value of the decision. In a lab experiment using real money and charities, participants (n = 297) were first given an endowment to split between themselves and a charity from a large list. Subjects then received new information about the charities’ financial efficiency and were allowed to modify their initial decisions. Those in the treatment groups were required to stand up at the end of the experiment and announce either the amount they donated, or both the donation amount and the efficiency information received in the second phase. For the control group, (donation decisions were private), receiving information about the expense efficiency of a charity increased average donation amount. However, when donation amount and efficiency information were made public, and thus had social-signalling value, there was a mixed reaction from donors, resulting in no overall effect on donation amount. (Butera and Horn 2017)


  • Expertly curated giving lists may increase donor confidence and generosity. In several field and lab experiments, ideas42 offered donors short, curated lists of charities. Some lists were curated by named philanthropic or sector-area experts; others were curated by celebrities or anonymously. (ideas42 2020)
  • Sharing information about major supporters validates your organization. In one large-scale natural field experiment, researchers sent direct mail solicitations to new donors who were unfamiliar with the fundraising charity (n = 61,483). One group of donors was told that contributions would be matched by the Bill & Melinda Gates Foundation (BMGF), and a second group was informed of an anonymous match. Those who were informed that BMGF was the source of match funding were 39% more likely to donate and donated on average 44% more than those who did not know the identity of the match donor. This experiment suggests that the public match campaign, which implied that a major institution viewed the charity favorably, provided a credible quality signal for new donors (Karlan and List 2018).


  • Reminding people of their past behavior as “donors” increases contributions. In a large-scale field experiment conducted with the American Red Cross (ARC), researchers sent direct mail solicitations to individuals who had previously donated to the ARC but had not contributed in the last 24 months (n = 17,061). All letters used the greeting, “Dear Friend and Supporter,” but one set of letters also included the note, “Previous Gift: [date]” below the postal address. Researchers found that including this extra line reminded donors of their identity as supporters of the ARC and increased the probability of a donation by 20%. Average donation amounts also increased by about 4.1% (Kessler and Milkman 2014).
  • Reminders encourage participation. In a field experiment, researchers sent out emails soliciting donations for a large Danish charity (n = 29,057). One group of people received an email reminder in addition to the original message. This increased both the likelihood of giving (by 50%, or 0.2 percentage points) and the total amount raised (Damgaard and Gravert 2014).
  • Photographs that elicit emotion increase donations. In one lab experiment (n = 11), subjects were given $15 dollars each and told it was theirs to keep but that any portion they chose could be donated to an orphanage in Sudan. During the experiment, subjects were shown both photographs and silhouettes of individual beneficiaries. Subjects were more than twice as likely to donate when viewing photographs, compared to silhouettes. Neural imaging and follow-up surveys (n = 22) indicated that photographs elicit stronger positive emotions, leading to more generosity (Genevsky, Vastfjall, Slovic, and Knutson 2013).
  • Sharing information about an “identifiable victim” heightens emotions. In one lab experiment, researchers asked participants to donate to sick children in need of an expensive medicine (n = 153). Different groups were shown an identified individual (i.e. name, age, picture), an unidentified individual, a group of identified individuals, or a group of unidentified individuals. The identified individual elicited the most donations, which researchers suggest is due to an intensified emotional response from participants. (Kogut and Ritov 2005).


  • Donation amounts are higher when choices are made in groups. In an online experiment, participants (n=1,109) were informed about climate change and the option to purchase carbon offsets. They were then randomly assigned to one of three different decision mechanisms: 1) They made an individual choice about the quantity of offsets to buy (individual); 2) Within a group of 9, each member voted on their preferred quantity and the median was bought (majority); 3) Within a group of 9, each member voted on their preferred quantity, but one vote was picked at random for the decision (dictator). Those in the majority and dictator groups made significantly greater contributions than those in the individual group (12% and 17% more respectively). Comparing contributions to beliefs, participants in the individual group contributed significantly less than they believed others would contribute, while participants in the majority group contributed what they believed others would contribute, and participants in the dictator group contributed significantly more than they believed others would contribute. (Ponitzsch 2017)
  • Lottery prizes increase the likelihood of giving. Researchers studied the effects of lotteries on donations in a door-to-door fundraising campaign for a local institution (n = 2,149). One group of households was informed that each dollar contributed would secure a lottery ticket for a $1,000 prepaid credit card. 45.5% of these lottery-offer households participated, compared to only 25.3% of households who were simply asked to donate. Similarly, the average donation per contact was 87% greater in the lottery treatment compared to the group with the standard ask. (Landry, Lange, List, et. al 2005).


  • Asking to donate future income at a later date increases participation. In a lab experiment (n=352), participants were asked to donate $5 of their participation fee for that day’s session to charity. Another group was asked to donate $5 out of their participation fee from the next week’s session. The one-week delay in charitable gift transaction increased participation from 31% to 45% — a 50% increase in giving. The researchers propose a model of social signaling in which donors receive social utility from deciding to give now, in addition to the warm glow of actual giving at a later time. (Andreoni and Serra-Garcia, 2018)
  • Asking donors to “Give More Tomorrow” encourages generosity. In one field experiment with a large and well-known Swedish charity, fundraisers called monthly contributors and asked them to increase their recurring donation amounts (n = 1,134). One group was simply asked to give more if possible, implying an immediate increase. A separate group was asked to give more if possible “beginning in January,” providing a two-month delay. Donors exhibited present-biased behavior: average increases in giving were 32% higher for those offered a delayed start, compared to those who were asked to give more immediately. This was driven both by greater participation and larger increases (Breman 2006).


  • Offering public recognition increases donations. In a field experiment, members of a service club at Yale University contacted alumni and asked them for donations that would go to support various student groups on campus (n = 4,168). Some people were told that donors contributing above a certain threshold would be listed in the service club’s newsletter. Compared to those who received only a plain ask for donations, those offered recognition were 2.7 percentage points more likely to give and gave on average 14 percentage points higher amounts (Karlan and McConnell 2013).
  • Considering a volunteer experience activates an emotional mindset and increases generosity. Researchers provided study participants with information about a charitable organization (n = 199). One group of participants was asked how much time they would give to the charity, while the other was not prompted to consider volunteering. Both groups were then asked how much money they would donate to the charity. Those who had first considered volunteering offered 49% more money than those who were only asked to donate. Follow-up studies measured actual donation activity with similar findings (n = 193). Researchers conclude that thinking about volunteering triggers an emotional mindset and prompts people to seek meaning and satisfaction, with positive effects on monetary donations. In contrast, thinking primarily about financial contributions triggers a value-maximization mindset and suppresses donations (Liu and Aaker 2008).
  • Non-monetary upfront gifts encourage donations. In this experiment, researchers conducted a direct-mail solicitation campaign (n = 9,846). Each household was randomly assigned to receive a letter alone, a small gift (a postcard and envelope) along with the letter, or a large gift (four postcards and envelopes) along with the letter. Recipients of the small gift donated at a 17% higher rate than recipients in the no-gift condition, and recipients of the large gift donated at a 75% higher rate than those in the no-gift condition. The researchers conclude that this “gift-exchange” activates desires to reciprocate the charity’s generosity (Falk 2007).

Rounding Up

  • Donors are more generous with windfall money than with earned income. In a lab experiment (n=188), students were asked to give to a disaster relief charity with windfall money or with money earned from a real task. They were given two different randomized tasks: in one, participants were granted a windfall before donating, and in the other they earned a variable amount of money based on their performance in a counting task before donating. Participants were more likely to give, and gave 29% more when they received the windfall money (Li et al. 2018).


  • Even minor inconveniences can depress giving. In a door-to-door fundraising campaign (n = 1,536), volunteers asked households to support a local charity that provides blankets to families in need. Solicitors explained that holiday cards would accompany the blankets funded by donors. They told the control group that cards had been pre-written, but gave the treatment group the option of writing messages. Contrary to the researchers’ hypothesis, households in the treatment group were 20% less likely to donate. They concluded that the opportunity to write a card may drive up the cost of giving in multiple ways: 1) more social pressure to accompany the personal gesture with a larger gift amount, 2) increased time to complete a transaction, and/or 3) additional need to make two decisions—whether to give, and whether to write a card—rather than one (Chuan and Samak 2014).
  • Making it easier to donate encourages participation. In field experiments conducted with a direct mail fundraising campaign in Germany, researchers tested two tactics designed to help people follow through on their intentions to give. In the first study (n = 5,000), researchers sent follow-up letters reminding people about the campaign. The reminders generated responses and increased response rates by 46%. In another experiment (n = 25,000), researchers added pre-filled bank transfer forms to some solicitation letters and gave people the option to donate with a credit card over the phone. People who received these additional tools were 26% more likely to respond, compared to those who received only a solicitation letter (Rasul and Huck 2010).


  • Lead gifts encourage participation and higher donation amounts. Researchers ran a direct mail fundraising campaign for the Sierra Club (n = 3,000) in which some letters described a match offer, with every dollar in donations later matched by a dollar from a lead donor. In other letters, researchers referenced a “challenge gift” already contributed by a lead donor. Mentioning a challenge gift increased participation rates by 23% and total contributions by 18%, compared to a plain ask. The challenge gift also outperformed the total amount raised under the match offer by 31%, although this difference was not statistically significant. (Rondeau and List 2008).
  • Individuals are more generous if they feel they are earning directly for charity rather than donating income they have already earned. In a lab experiment (n = 246), participants selected a charity and performed a 75-minute effort task, which earned them money. Some participants could only donate from their earnings at the end of the experiment (with and without a reminder of their charity choice), some were able to donate earnings at any time and were reminded of their charity choice, and some were able to switch where their earnings were going to, themselves or their charity choice, at any time. The final condition, in which subjects could choose to direct their efforts directly to the charity, resulted in higher donation rates and amounts than all other conditions (Brown et al. 2013).