Item Response Theory for Peer Assessment

Item-response theory is applied to peer assessment by a new method for estimating assessment-criterion parameters. The proposed model is a modified graded item response model with an assessorpsilas evaluation-criterion parameters. The advantages of this method are as follows: (i) the capability of evaluating learnerspsila abilities on the same scale even if the assessors have different assessment criteria; (ii) evaluating the learnerspsila abilities by considering each assessorpsilas characteristics, thus giving reliable evaluated results; and (iii) easy estimation of the parameters from missing data. As a result of these advantages, the proposed method improves the accuracy of peer assessment. The proposed model was compared with conventional methods, and the proposed method showed the best performances.