Fig. 3

Item maps with distributions of person parameter locations and information curve above item threshold locations. Notes. Person parameters are weighted maximum likelihood estimates and illustrate the distribution of these for the study sample (black bars above the line) and for the population under the assumption of normality (grey bars above the line), as well as the information curve, relative to the distribution of the item difficulties (black bars below the line). For the PS subscale, item maps are shown in subgroups for which evidence of DIF was found within each of the two samples