Longitudinal Multistage Testing

This article introduces longitudinal multistage testing (lMST), a special form of multistage testing (MST), as a method for adaptive testing in longitudinal large-scale studies. In lMST designs, test forms of different difficulty levels are used, whereas the values on a pretest determine the routing to these test forms. Since lMST allows for testing in paper and pencil mode, lMST may represent an alternative to conventional testing (CT) in assessments for which other adaptive testing designs are not applicable. In this article the performance of lMST is compared to CT in terms of test targeting as well as bias and efficiency of ability and change estimates. Using a simulation study, the effect of the stability of ability across waves, the difficulty level of the different test forms, and the number of link items between the test forms were investigated.