Measurement invariance of the Schizotypal Personality Questionnaire in Asian, Pacific Islander, White, and multiethnic populations.

The Schizotypal Personality Questionnaire (SPQ; Raine, 1991) is one of the most commonly used self-report measures of schizotypal personality traits. Previous work has found that the SPQ has a 3- or 4-factor structure, but most of this work was with White participants. Little is known about the psychometric properties of the scale in Pacific Islander populations, and some evidence suggests scores may differ between White and Asian participants. The current study included 398 Asian, 293 White, 159 Pacific Islander, and 308 multiethnic nonclinical participants. A 4-factor model fit the data well, and this factor structure displayed configural and metric invariance, suggesting that the factor structure is the same across these diverse groups. However, results provided mixed evidence for scalar invariance, suggesting the scale may lack scalar invariance in these populations. Follow-up analyses revealed that the questionable scalar invariance was related to the intercepts of the Ideas of Reference and Suspiciousness subscales in the White sample. This suggests that mean comparisons among ethnic groups involving the Ideas of Reference and Suspiciousness subscales are not appropriate.