Evaluation of measurement precision with Rasch-type models: The case of the short Generalized Opinion Leadership Scale

Item response theory (IRT) forms a flexible psychometric modeling approach to construct and evaluate new assessment instruments. This paper demonstrates how to evaluate the measurement precision of personality scales by assessing their test–retest error and their convergence across different raters within an IRT framework. The first study (N = 1575) reports on the construction of a new personality scale to assess generalized opinion leadership by fitting a polytomous Rasch model to the data. Furthermore, in two independent samples the psychometric properties of the scale are evaluated by applying the linear partial credit model. In a retest design the amount of transient error, that is, systematic measurement error specific to a single measurement occasion, is quantified within an IRT framework (study II, N = 586) as well as the convergence of self-and observer-ratings of the trait (study III, N = 400).