Regression Effects in Angoff Ratings: Examples from Credentialing Exams

摘要

This article discusses regression effects that are commonly observed in Angoff ratings where panelists tend to think that hard items are easier than they are and easy items are more difficult than they are in comparison to estimated item difficulties. Analyses of data from two credentialing exams illustrate these regression effects and the persistence of these regression effects across rounds of standard setting, even after panelists have received feedback information and have been given the opportunity to discuss their ratings. Additional analyses show that there tended to be a relationship between the average item ratings provided by panelists and the standard deviations of those item ratings and that the relationship followed a quadratic form with peak variation in average item ratings found toward the middle of the item difficulty scale. The study concludes with discussion of these findings and what they may imply for future standard settings.