This article proposes a model-based procedure, intended for personality measures, for exploiting the auxiliary information provided by the certainty with which individuals answer every item (response certainty). This information is used to (a) obtain more accurate estimates of individual trait levels, and (b) provide a more detailed assessment of…

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…