Figure 4

Effort repartition. The 4 panels represent the Lorenz curves of individual user contribution to positive progress (i.e. the number of correct links assembled) for the different puzzles, and the corresponding Gini index. The Lorenz curve represent the cumulative distribution of the positive progress of users, where users are ordered increasingly along this measure on the x-axis. It exhibits the relative importance of difference in contribution to total progress across users. The Gini index is the proportional area between an hypothetical uniform repartition (red line) and the actual repartition (Lorenz curve, in black). A high Gini index indicates a high inequality in the contributions of different users.