Standard-Setting Procedures for Counts Data.

ABSTRACT

An examinee- and an item-centered procedure are proposed to set cut scores for counts data. Both procedures assume that the counts data are modelled according to the Rasch Poisson counts model (RPCM). The examinee-centered method is based on Longford's (1996) approach and links contrasting-groups judgements to the RPCM ability scale using a random logistic regression model. In the item-centered method, the judges are asked to describe the minimum performance level of the minimally competent student by giving the minimum number of correct responses (or, equivalently, the maximum number of admissible errors). On the basis of these judgements for each subtest, the position of the minimally competent student on the RPCM ability scale is estimated. Both procedures are illustrated with a standard-setting study on mental arithmetic for students at the end of primary education.