Using the Rasch analysis for the psychometric validation of the Irregular Word Reading Test (TeLPI): A Portuguese test for the assessment of premorbid intelligence

Objective: The present study aims to analyze the psychometric characteristics of the TeLPI (Irregular Words Reading Test), a Portuguese premorbid intelligence test, using the Rasch model for dichotomous items. Results: The results reveal an overall adequacy and a good fit of values regarding both items and persons. A high variability of cognitive performance level and a good quality of the measurements were also found. The TeLPI has proved to be a unidimensional measure with reduced DIF effects. Conclusions: The present findings contribute to overcome an important gap in the psychometric validity of this instrument and provide good evidence of the overall psychometric validity of TeLPI results.