[vismwasm]

The author measures the Dunning Kruger effect on his random data exactly because he assumes it when generating his random data.

By modelling skill and perceived skill as uniform draws between 0 and 100, the unskilled (e.g. skill=0) will over-estimate their skills (estimated skill = 50, the mean on the uniform random variable) and the skilled (e.g. skill=100) will underestimate it (as 50 as well, again the mean of the same random variable). The only ones who will be correct (on average) are the average skilled ones (skill=50).