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…

The present study has two main interests. First, some pending issues about the psychometric properties of the CTAC (an anxiety questionnaire for blind and visually-impaired people) are assessed using item response theory (IRT). Second, the linear model is compared to the graded response model (GRM) in terms of measurement precision, sensitivity…

This article describes a model for response times that is proposed as a supplement to the usual factor-analytic model for responses to graded or more continuous typical-response items. The use of the proposed model together with the factor model provides additional information about the respondent and can potentially increase the accuracy of the…

Trait psychology implicitly assumes consistency of the personal traits. Mischel, however, argued against the idea of a general consistency of human beings. The present article aims to design a statistical procedure based on an adaptation of the pi* statistic to measure the degree of intraindividual consistency independently of the measure used.…