This dissertation is composed of a study of estimation methods in classical and test theories and the elaboration and application of a cluster-robust variance estimator. Variance estimators derived from generalized estimating equations are known to be robust to most covariance structures and are therefore well suited for psychometric analysis of…

The research project presented in this article was set in the Swedish school context and carried out on a set of compulsory national tests for English, Swedish, and mathematics used at the end of compulsory school. The aims were: (a) to gain a deeper knowledge of the internal structure of the tests and (b) to separate individual performance from…