Using item response theory to develop and test a realistic vocational interest scale

Vocational interest has been extensively studied within the fields of psychology. However, the development of scales focusing on specific interests remains limited, particularly for instruments developed using Item Response Theory (IRT). The present study aimed to clearly define and develop Realistic Vocational Interest among middle school students, examine its dimensionality and IRT properties, and compare its measurement information with that of existing instruments. Data from 1,248 middle school students were included in the data analysis. This study used the Graded Response Model (GRM) to fit the data and examined the IRT parameters for each item, including the Item Characteristic Curve and Information Functions. Through evaluations of unidimensionality, monotonicity, local independence, and item fit, an 11-item short form (RIS-11) was finalized. The RIS-11 demonstrated high internal consistency reliability (α = 0.960). Comparative analyses revealed that the RIS-11 provides greater informational value compared to both the Realistic subscale of the Chinese version of Holland’s RIASEC and the Su’s SETPOINT model subscale of practical operations interest. In conclusion, the RIS-11 represents a reliable and psychometrically sound instrument developed within a cultural context to assess realistic vocational interest among middle school students.