Psychometric validation and exploratory application of the Professional Identity Questionnaire (PIQ) among nursing students and early-career nurses

Professional identity is a fundamental outcome of health professions education and plays an important role in professional commitment, resilience, ethical practice, and workforce retention. Culturally adapted and psychometrically robust instruments are essential for assessing professional identity across different contexts. This study aimed to translate, culturally adapt, and psychometrically evaluate the Persian version of the Professional Identity Questionnaire (PIQ) among undergraduate nursing students and to explore its application among early-career nurses. A two-phase cross-sectional study was conducted at Shahid Sadoughi University of Medical Sciences in 2025. In Phase I, the Persian PIQ was translated and culturally adapted according to Beaton’s guidelines. Face and content validity were assessed using qualitative and quantitative approaches. Structural validity was examined using confirmatory factor analysis (CFA) in 226 undergraduate nursing students. Internal consistency was assessed using Cronbach’s alpha, and test–retest reliability was evaluated in an independent sample of 100 nursing students using the intraclass correlation coefficient (ICC). In Phase II, the Persian PIQ was administered to a separate sample of 110 early-career nurses as an exploratory application to describe professional identity and examine its associations with demographic and occupational characteristics. Correlation and multiple linear regression analyses were used to explore these associations. Statistical significance was defined as a two-sided p-value < 0.05. All items met the predefined criteria for face and content validity. CFA supported the hypothesized two-factor structure comprising Professional Identity Formation Attachment (PIF-A) and Professional Identity Formation Detachment (PIF-D), with good model fit (χ2/df = 1.08, RMSEA = 0.01, CFI = 0.99, IFI = 0.99, GFI = 0.97, SRMR = 0.04). Standardized factor loadings ranged from 0.30 to 0.90. Internal consistency was good for the total PIQ (Cronbach’s α = 0.86), with α = 0.93 for PIF-A and α = 0.78 for PIF-D. Test–retest reliability was satisfactory for the total scale (ICC = 0.79, 95% CI: 0.71–0.85). In Phase II, the mean total professional identity score was 38.67 ± 6.77 (possible range, 10–50). Work experience showed a small positive association with the reverse-scored PIF-Detachment dimension (r = 0.250, p = 0.008). It remained positively associated with this dimension in the regression analysis (β = 0.250, B = 0.644, 95% CI: 0.164–1.125, p = 0.009). However, the overall regression model was not statistically significant (R2 = 0.063, adjusted R2 = 0.037, p = 0.073). Age and sex were not significantly associated with professional identity outcomes. The Persian version of the PIQ demonstrated supportive evidence of content and factorial validity, internal consistency, and test–retest reliability among Iranian undergraduate nursing students. Its exploratory application among early-career nurses provided preliminary descriptive and associative evidence regarding professional identity in a clinical population but did not constitute additional psychometric validation. The positive association between work experience and the reverse-scored PIF-Detachment dimension should be interpreted cautiously given its modest magnitude, the nonsignificant overall regression model, and the cross-sectional design. Further validation in larger and more diverse nursing populations, including formal measurement-invariance testing and additional sources of validity evidence, is warranted before broader comparative or intervention-based applications. Not applicable.