Figure 1: The steps for the method of Douglas and Mislevy: (a) distribution of the test scores for two tests; (b) estimation of the true values and definition of master/non-master according to the model; (c) distribution of the scores achieved by masters; (d) distribution of the scores achieved by non-masters (note: perspective is different). The distribution of the overall results (a) is comprised of the scores achieved by masters and non-masters.