Experimental Design
Step 1: Explain experiment to participants. This step consists of informing participants of the broad goals of the study, obtaining their consent, and explaining the types of decisions they will make. We will tell participants we are studying decision-making about charitable giving, though we will not explain that we are interested in the effect of defaults, because this could bias participant behavior. We want participants to respond to the presence of a default option “naturally,” meaning similar to how they would in non-experimental contexts. If we inform participants that we are studying defaults, they may determine they should ignore the default. When explaining decisions, we will tell them that they will make a series of binary decisions between bonus rewards. We will tell them (truthfully) that there is a 5% chance one of their decisions will be implemented, and which decision is implemented will be selected at random. We will tell them (truthfully) that it is in their best interest to choose the alternative they truly prefer. We will explain the use of the gift card (a GAP gift card), and the work done by the charity (GiveDirectly). Participants will thus by fully informed about the properties of the options in decisions.
Step 2: Calibration question. It is crucial in our experiment that differences in default effects cannot
be explained by differences in the relative (active choice) valuation of the two alternatives in the self-self
and self-other decision. Therefore, we will first ask a calibration question via multiple price list so that for each participant, the
participant values $50 for charity and gift card for self equally.
Step 3: Randomize into treatment cell. We will randomize the participant into one of the treatment conditions: 1) Default Cash - Self vs Other choice, 2) Default Charity - Self vs Other choice, 3) Default Cash - Self vs Self choice, 4) Default Gift Card - Self vs Self choice. This will determine only the first binary decision they will make post- calibration.
Step 4: First binary decision. The participant will be told, for example: “We offer you a bonus of $5.00 in money for yourself. Alternatively, you can instead choose as your bonus a $50.00 donation to GiveDirectly. Below you can decide if you want the default bonus or the alternative.” The participant will then see the two alternatives next to radio buttons, followed by a “continue” button. The top radio button will be automatically selected and the participant will be free to select “continue.”
Step 5: Additional binary decisions. The participant will make a series of similar decisions in random order. Each decision will vary along the following dimensions: the default condition and the tradeoff condition. We will also include some “dummy decisions”—i.e., decisions we do not plan to analyze—to keep the participant from easily recalling previous decisions. We will randomize the order of decisions.
Step 6: Demographics questions. We will conclude with some straightforward demographic questions about gender, race, ethnicity, age, and education so that i) we know how well our sample corresponds to average Americans, ii) to see if effects vary across demographics, iii) to control for demographics in the analysis to add power, to the extent that demographics predict decisions.