Test-retest studies for assessing stability and change are widely used in different domains and allow improved or additional individual estimates of interest to be obtained. However, if these estimates are to be validly interpreted the responses given at Time-2 must be free of retest effects, and the fulfilment of this assumption must be…

This article proposes procedures for simultaneously assessing and controlling acquiescence and social desirability in questionnaire items. The procedures are based on a semi-restricted factor-analytic tridimensional model, and can be used with binary, graded-response, or more continuous items. We discuss procedures for fitting the model (item…

A theoretical advantage of item response theory (IRT) models is that trait estimates based on these models provide more test information than any other type of test score. It is still unclear, however, whether using IRT trait estimates improves external validity results in comparison with the results that can be obtained by using simple raw…