New Generic Scale Measures Professional Identity in Chinese University Students

A study published in BMC Psychology by Yanan Deng, Jinyan Huang and Chen Cheng reports the development and validation of a new instrument for measuring professional identity in Chinese university students: the Professional Identity Generic Scale, or PIGS. The authors start from the observation that professional identity can begin to form before entry into full professional practice, and that cross-domain measures for university students must distinguish this emergent identity from identification with an academic major or discipline while accommodating a strong general factor. The scale was evaluated with modern psychometric methods spanning factor analysis and item response theory.

The researchers began with a pool of 42 candidate items, which they examined in a construction sample of 836 students. From this pool they distilled a 34-item version of the scale, which was then evaluated in a validation sample of 1,533 students. The analytical strategy was deliberately layered. The team ran oblique exploratory factor analysis to see how the items clustered, tested competing confirmatory factor models, computed bifactor reliability indices to quantify how much variance reflected a single general construct, and carried out content-validity checks alongside sensitivity analyses for uniform response profiles, a safeguard against students who endorse every item the same way.

A key tension emerged between statistics and theory. Parallel analysis, a statistical criterion for deciding how many factors to retain, suggested three broad factors underlying the item responses. Yet an exploratory solution guided by the researchers’ theoretical blueprint preserved the intended six content domains. The authors resolved this with a bifactor confirmatory model, which allows every item to load simultaneously on one general professional-identity factor and on narrower domain-specific factors. This model provided the best approximate fit, with a comparative fit index of 0.942, a Tucker-Lewis index of 0.934, a root mean square error of approximation of 0.059 and a standardized root mean square residual of 0.034. The bifactor reliability indices then clarified what the scale measures: omega hierarchical, which isolates reliability attributable to the general factor, reached 0.936, and the explained common variance of the general factor was 0.771, both supporting a strong general score. By contrast, domain-specific omega hierarchical values ranged only from 0.050 to 0.344, indicating that after the general factor is accounted for, the six domains carry little unique, reliable signal of their own.

To probe the items at a finer grain, the team fitted a confirmatory bifactor graded response model, an item response theory approach suited to ordered rating-scale responses. This analysis explicitly examined ordered response thresholds and category functioning, item information, local dependence between items, and differential item functioning across subgroups. On the general axis, item discriminations ranged from 1.81 to 3.72, and response thresholds spanned from −4.30 to 2.04 in the expected order, meaning the response categories functioned monotonically across the trait range. The global correlation root mean square residual was 0.050. Local dependence was minimal: only one adjusted Q3 pair, involving Items 29 and 31, exceeded the 0.20 threshold, at 0.207. No gender or study-stage differential item functioning effect reached the prespecified practical criterion of a change in R-squared of 0.02 or greater, suggesting the items performed comparably across these groups.

The authors’ conclusion is carefully scoped. Within the sampled Chinese university-student context, the PIGS is best interpreted as a measure of a strong general professional-identity construct sampled through six theoretically specified content domains. The total score is the principal score supported by the evidence; summaries of the individual domains may be used descriptively, but not as independent latent scales. By combining exploratory and confirmatory factor analysis, bifactor reliability decomposition, and an item response theory evaluation that explicitly tested threshold ordering, item information, local dependence and differential functioning, the authors provide a transparent account of what each score from the scale can and cannot support. The validation evidence establishes the psychometric foundation for the instrument within the sampled context, while generalization to other populations and settings remains a standard open question for any newly developed scale.

Subject of Research: Development and validation of the professional identity generic scale for chinese university students: Factor-analytic and item response theory approaches

Article Title: Development and validation of the professional identity generic scale for chinese university students: Factor-analytic and item response theory approaches

Article References: Deng, Y., Huang, J., & Cheng, C. (2026). Development and validation of the professional identity generic scale for chinese university students: Factor-analytic and item response theory approaches. BMC Psychology. https://doi.org/10.1186/s40359-026-05831-5

Image Credits: AI Generated

DOI: 10.1186/s40359-026-05831-5

Keywords: Development, validation, professional, identity, generic, scale, chinese, university, students, Factor-analytic, item, response