Psychometric evaluation of an Indonesian version of the Brief Self-Control Scale: Item calibration using polytomous Rasch models

Abstract

This study aimed to evaluate the psychometric properties of the 10-item Indonesian version of the Brief Self-Control Scale (BSCS). It used the polytomous Rasch model, which enables more detailed analysis, including differential item functioning (DIF) analysis. The participants in this study were 1001 Indonesian high school students. We found that the partial credit model (PCM) was a better fit than the rating scale model. Furthermore, the unidimensionality, local independence, and monotonicity assumptions of the PCM were valid for the BSCS. Q5 was the only item that did not fit the PCM. The step parameters of the BSCS functioned well, with values ranging from low to high, as expected, for all items, indicating monotonicity. Person separation reliability was 0.71, indicating that the BSCS has good internal consistency. The DIF analysis showed that item Q5 functioned differently across genders. In general, the remaining nine items of the BSCS have good psychometric properties for measuring self-control.