Studying people is difficult, and studying fundraising can be particularly hard. People don’t always want to tell researchers about things related to money, and people sometimes claim to be more generous than they really are. In the real world, many different causes affect someone’s decision to give or not to give money, disentangling all the possible causes can be difficult. Scientists use several methods to get to the truth: field experiments, lab experiments, surveys, and interviews.
Field experiments: Field experiments are the “gold standard” of research on fundraising because they combine the scientific rigor of laboratory experiments with a focus on real-life behaviors. In a field experiment involving fundraising, the list of donors is randomly divided into groups and each group gets asked to donate money in a slightly different way. For example, one might test the effects of different language in a fundraising letter by dividing a group of donors randomly in half and sending one half one letter and the other half a different letter. By randomly dividing the groups, any differences between the individuals in each group tend to average out, particularly if the groups are large. We present almost all the current field experimental research on this website.
Laboratory experiments: Like field experiments, laboratory experiments divide subjects randomly into groups and treat each group differently. Unlike field experiments, laboratory experiments do not examine real-world donors making actual donations; they usually use college students as subjects and give them opportunities to donate small amounts, often just a raffle ticket, to charity. Because college students are different from most donors, and because giving away a raffle ticket is different from giving away one’s own hard-earned money, laboratory experiments are less useful than field experiments in telling us how real donors behave.
Surveys: Surveys take a large random sample of a country’s population and ask the subjects in the sample questions about their charitable giving. The best surveys are “longitudinal,” which means they come back to the same group of subjects two or more times over a period of years and see how their charitable giving changes over time. The advantage of surveys is that they study real-life behaviors. There are two main disadvantages, however: self-attribution bias and the complexity of real life. “Self-attribution bias” means that people tend to describe themselves as more generous than they really are, so people often exaggerate their charitable giving on surveys. The complexity of real life means it can be hard to tell what changes in a person’s life really causes changes in charitable giving. Take, for example, the fact that married people with children tend to give more money to charity. Is it because they are married, because they have children, or because they were more generous to begin with, which made them more likely to get married and more likely to have children? Scientists use longitudinal studies and complex statistical methods to disentangle these effects but the process is not perfect.
Interviews: Sometimes the best way to find out why someone does something is just to ask them. Some very good interview studies get at processes that are impossible to test through lab or field experiments, and too complex to examine through survey research. Two examples are the studies of how married opposite-sex and same-sex couples make decisions about charitable giving, which are summarized in our post on married donors. The problems with interview studies is that they usually use small and non-representative samples, and that people tend to present themselves to interviewers as more generous than they actually are.
So you can see that none of these four methods is perfect. In this website we give priority to field experimental studies, as these are the most valid and reliable, but we also report the results of lab experiments, surveys, and interview research.