Psychometric evaluation of the pictorial scale of perceived movement skill competence in Chinese children: An item response theory analysis.

Abstract

This study aimed to investigate the psychometric characteristics of the Pictorial Scale of Perceived Movement Skill Competence (PMSC) in Chinese children, utilizing the principles of item response theory (IRT). A total of 284 children (147 boys), aged 4-10years (Mage = 7.39, SD = 2.18), from four schools were recruited for testing, adhering to the principle of random sampling. The Rasch model was applied to evaluate the rating scale validity, local independence, scale dimensionality, person and item fit statistics, and differential item functioning (DIF). (1) The rating scale validity was confirmed by the monotonically increasing trend in both average item difficulty measures and Andrich thresholds. (2) However, the observation that standardized residual correlations for all items remained below 0.3 unequivocally confirmed the presence of local independence among the variables. (3) The scale's dimensions were substantiated, with Rasch measures explaining 40.6% of total variance, exceeding the 40% threshold. Additionally, the first contrast had an eigenvalue of 1.8 and explained 8.80% of the variance, both exceeding the minimum 3:1 ratio. Consequently, the unidimensionality assumption of the item was supported. (4) Person and item fit statistics indicated requisite reliability and separation, with all achieving suitable infit and outfit measures, and point-biserial correlations exceeding 0.55. (5) Regarding gender DIF, it was observed that the majority of items did not exhibit statistically significant gender DIF effects (p > 0.05) except item 8 (Bounce a ball, t = -2.74, p < 0.01, DIF = -0.51). Rasch analysis revealed that the instrument exhibited strong scale validity among Chinese children, adhering to the Rasch model's unidimensionality and local independence principles, with robust person and item reliability and separation. All items demonstrated a good fit. Additionally, the significant gender difference in item 8 (Bounce a ball) warrants further consideration. In conclusion, PMSC is suitable for assessing the PMSC of Chinese children.