Experimental Design Details
The real effort task I refer to in the description below is a task that consists in counting how often a given character appears in a matrix that contains different characters. The tasks are chosen such that subjects in the pilot take roughly 45-70 seconds to complete one task.
The design consists of a sign-up session, three main sessions, and a final debriefing survey. In the sign-up session I get subjects’ consent to participate; I describe the study, the type of task they will be asked to complete, and the choices they will be asked to make; and I test their comprehension. Those subjects that pass the comprehension test can enroll in the study, the others are excluded.
Moving on to the experiment, the main outcomes of the design are between-subjects. Every participant who signs up will be asked to do tasks in 3 sessions. In all sessions, subjects have to do a given amount of required tasks. I randomize at the individual level whether subjects exert low effort in the first session and high effort in the second; or high effort in the first session and low in the second. Since the total amount of work is kept the same for all, this rules out the possibility that different choices over future work are driven by learning. However, if subjects who worked more in session 2 are more tired, then projection bias predicts that they will be less willing to accept to do extra work at the end of session 3. Therefore, at the end of session 2 I will elicit the willingness to work (WTW) more right away (at the end of session 2), as well as the WTW more in session 3. The degree to which the session 2 WTW predicts session 3 WTW gives a *direct* measure of the population-average projection bias.
In session 3, subjects complete the work they signed up for and then complete the debrief survey.
I will run the following:
- I elicit the WTW after subjects have done 10, 40, and 70 tasks
- I test 3 methods of eliciting WTW, see below.
Elicitation methods that I test in the Pilot to see whether they give consistent/coherent answers:
1. Price list where the number of tasks are fixed and the payments varied
2. Multiple piece-rates for the task, and subjects state the number of tasks they are willing to do (Augenblick and Rabin (2018))
3. Subjects report directly the smallest payment for which they are willing to do a fixed amount of work
Based on the pilot, I will choose choose the effort level as well as the *primary* elicitation method in order to maximize the power of test. One of the identifying assumptions is that people's WTW fluctuates as they do more work. If this is not the case, then projection bias predicts the same as no projection bias. The primary elicitation method is either going to be 1 or 3 -- the multiple piece-rates does not allow to estimate individual or group-level projection bias estimates without functional form assumptions, and thus will be included only as a control, as will the elicitation method that does not provide the most precise information. The reason for including all 3 methods (with the primary method getting half the choices, and the other two methods getting the remaining half of the choices) is in part as a consistency check, and in part to alleviate measurement error as highlighted in Gillen, Snowberg, and Yaariv (2019).