Abstract
Background: Criminal aptitude testing benefits police and other fields of law enforcement. Earlier literature lacked an Urdu-language scale for criminal aptitude. Objectives: The present study developed and validated a new scale to measure criminal aptitude in Urdu speakers. Methods: The development and validation of the Criminal Aptitude Inventory (CAI) unfolded across three distinct phases, involving a total of 1675 participants (51.34% women), including convicted prisoners (37.33%). In the initial phase, the CAI underwent development and preliminary validation through exploratory factor analysis (EFA). Subsequently, the second phase utilized Confirmatory Factor Analysis to further confirm the scale's validity. The third phase focused on analyzing the CAI's convergent and discriminant validity by investigating its relationship with antisocial personality disorder, morality, religiosity, and spirituality. Results: The results demonstrated high reliability and validity of the CAI, affirming its suitability for future applications. The final version of the scale comprises a single factor and consists of 36 items, each utilizing a 5-point Likert-type response format. Indicators such as Kaiser-Meyer-Olkin's values (0.984), Cronbach’s alpha (0.984), average item-total correlation (P < 0.001), comparative fit index (0.936), Tucker-Lewis Index (0.932), Goodness of Fit Index (GFI=.939), root mean square error of approximation (RMSEA = 0.043), convergent validity with antisocial personality disorder (r = 0.458; P < 0.01), and discriminant validity with morality (r = -0.396; P < 0.01), religiosity (r = -.318; P < 0.01), and spirituality (r = -.453; P < 0.01) established the reliability and validity of the CAI. Conclusions: The dual-source data collection strategy employed in this study, drawing from both convicted prisoners and the general population, enhances and operationalizes the scale. This approach ensures its applicability across diverse Urdu-speaking communities in Pakistan and India.