Research

Working Paper
Marc Kaufmann. Working Paper. “Projection Bias in Effort Choices”.Abstract

Working becomes harder as we grow tired or bored. I model individuals who underestimate changes in marginal disutility - as implied by "projection bias" - when deciding whether or not to continue working. This bias leads to two mistakes. First, they are too pessimistic when they are tired and working is hard, and too optimistic when rested and work is easy. When within-day disutility is convex and individuals face a single task with all-or-nothing rewards (such as passing or failing a test), they initially underestimate the total disutility and start some overly ambitious tasks. As work becomes harder, they perceive the task as less worth completing and may quit. If the deadline for the task is far in the future, such individuals may repeatedly start working, yet quit earlier than anticipated. This can lead to large daily welfare losses. When tasks instead have concave rewards, including piece rates, such individuals work optimally if facing only a single task. But when working on multiple such tasks (for example, studying for two tests with continuous grades), they may mis-prioritize the tasks. In particular, they over-prioritize urgent tasks over important but non-urgent tasks, overestimating how much they will later work on the non-urgent tasks. Second, when tasks can be completed across multiple days, individuals smooth work too little over time. Because they underestimate how much the marginal disutility will increase on better days, they work too much on those days, and overreact to daily differences in opportunity costs, incentives, and productivity.

jmp-marc-kaufmann.pdf
Marc Kaufmann. Working Paper. “Estimating Projection Bias in a Real-Effort Experiment”.Abstract

I estimate the degree of projection bias in choices over tasks in an experiment with subjects from Amazon Mechanical Turk. People with projection bias misperceive their future disutility to be more similar to their current disutility than it is. I directly measure the disutility of effort for two different tasks, asking subjects to report their willingness to continue doing another set of tasks. At the beginning and end of each session, subjects also report their willingness-to-accept more tasks in the future. The change in the willingness-to-accept more tasks is directly proportional to the projection bias parameter and the change in how much people's immediate willingness-to-continue, which allows to estimate projection bias without needing to know the shape of the disutility.

Marc Kaufmann. Working Paper. “Same Value-Added, Different Value Added”.Abstract

Is a teacher's value-added the same for all students? Using test score data in mathematics for all students in grades 3 to 5 from a North Carolina, I test whether a teacher's value-added is the same for for male and female students, as well as white and black students by computing, separately, gender-specific and race-specific value-added estimates. While the correlation is quite high, following Kinsler (2013) I reject the hypothesis that they are the same. I find that a gender match between teacher and student increases test scores by around 1% of the standard deviation of year-by-grade test scores, while a race match increases test scores by around 5% of the standard deviation – holding the average value-added of the teacher constant.