The experiment will be conducted online using oTree and participants will be recruited using Prolific.
Participants are operating within groups of size three in which they have to decide how much to contribute to a public good. They make this decision in five different situations. The overall efficiency of contributions (i.e., the total benefits generated by each contribution) is the same in all five situations. The situations differ in the share of the benefits of the public good that goes back to the three group members; the remaining share is to be donated to a charity organization (Make-a-Wish). After decisions have been made, for each group the three members are paid out according to one randomly chosen decision situation.
Before being paid out, however, participants are given three more tasks. First, a short survey eliciting their numeracy, in particular, testing their understanding of ratios, probabilities and fractions. Second, a task where we elicit their giving type (e.g., warm-glow or altruistic). Third, few questions retrieving their opinion on classifying giving behaviour to charity in the presence of “rebates” and “matches”. Both instruments are often in place to encourage charitable giving, and are equivalent, but may be understood differently.
The current idea is, for the main task, to have all participants making all five decisions; that is, the “share” being a within-subjects variation. Our plan is to collect data in two waves. After the first wave, we will briefly investigate whether the within-subjects nature produces obscure behaviour. If not, we will continue collecting the remaining observations in a within-subjects format. Otherwise, we will consider switching to a between-subjects design. All information below concerns the within-subject design, and will be updated if and when we decide to switch to a between-subjects design.