Modeling judgments in the Angoff and Contrasting-Groups method of standard setting

摘要

Essential for the validity of the judgments in a standard-setting study is that they follow the implicit task assumptions. In the Angoff method, judgments are assumed to be inversely related to the difficulty of the items; contrasting-groups judgments are assumed to be positively related to the ability of the students. In the present study, judgments from both procedures were modeled with a random-effects probit regression model. The Angoff judgments showed a weaker link with the position of the items on the latent scale than the contrasting-groups judgments with the position of the students. Hence, in the specific context of the study, the contrasting-groups judgments were more aligned with the underlying assumptions of the method than the Angoff judgments.