The revised Edward Zigler Yale-Personality Questionnaire (EZPQ) for persons with intellectual disability: A new four-factor structure in confirmatory factor analysis

Zigler’s theory assumes that due to frequent negative personal experiences, persons with intellectual disability are likely to develop specific personality traits which hinder their functioning. The Edward Zigler-Yale Personality Questionnaire (EZPQ) is a measure that allows these traits to be assessed. However, studies in which the measure was used report problems with its factorial structure and reliability. We evaluated the psychometric properties of EZPQ in three consecutive studies conducted in three different samples of 336, 330, and 310 students with mild and moderate intellectual disability. By making successive modifications to the original version of the EZPQ, we developed and validated a revised four-factor version of the questionnaire that consists of 16 items (EZPQ-16R). The factors we identified corresponded to the following traits: readiness to explore, assignment alacrity, negative-reaction tendency, and support dependence. The reliability of the new gauge was high, and its validity was confirmed in correlational analyses with other measures of personality and adjustment. The four traits that were identified are directly derived from Zigler’s theory, thus giving a new perspective on the assessment of specific personality traits in persons with intellectual disability.