Psychometric properties of the Chinese subjective vitality scale among Hong Kong undergraduates using an item response theory approach

This study examined the psychometric properties of a Chinese version of the Subjective Vitality Scale (SVS) in measuring the general sense of subjective vitality among Chinese undergraduates in Hong Kong. Various scales including the Chinese SVS were administered through online questionnaires. The seven-item Chinese SVS was tested with Rasch analysis, with the criteria of information-weighted fit indices to examine its factorial and convergent validity. Results from the Rasch analysis were compared to those from the categorical confirmatory factor analysis (CFA). Differential item functioning and measurement invariance across genders were also examined. Moreover, concurrent validity was assessed by correlating SVS with other variables. Rasch analysis and categorical CFA showed that, after removing two items, the five-item SVS showed a good fit to the data. Strict measurement invariance across genders, good convergent validity, and adequate concurrent validity were also demostrated. This study shows that the five-item Chinese SVS is a psychometrically sound instrument among Chinese undergraduates. Further studies could be done based on this Chinese version of SVS.