Fig. 4

Simulation study effects of varying efforts, ability and what peers use to assess each other on ranking in class. The gray shading indicates the distribution of effort put in by others in the class (on an arbitrary scale); these distributions differ for panels (a) to (c) and for (d) to (f). The x-axes indicate the amount of effort put in by one focal student, on the same scale. Panels (a) and (d) are for a student in the 25%ile of ability, (b) and (e) for the median, and (c) and (f) for the 75%ile of ability. The colored lines signify scenarios in which team mates assess each other based on the effort they put in (red), their ability (blue) or their contribution (the product of the two, purple). In black is represented the rank if no peer review is used and the students are graded solely based on their team’s product