Psychometric properties of the Social Cognitive Theory questionnaire for physical activity in a sample of Iranian adolescent girl students

ABSTRACT

This research examined the validity and reliability of a researcher-developed questionnaire based on Social Cognitive Theory [SCT] to assess the physical activity behaviour of Iranian adolescent girls [SCT-PAIAGS]. Psychometric properties of the SCT-PAIAGS were assessed by determining its face validity, content and construct validity as well as its reliability. In order to evaluate factor structure, cross-sectional research was conducted on 400 high-school girls in Tehran. Content validity index, content validity ratio and impact score for the SCT-PAIAGS varied between 0.97-1, 0.91-1 and 4.6-4.9 respectively. Confirmatory factor analysis approved a six-factor structure comprising self-efficacy, self-regulation, family support, friend support, outcome expectancy and self-efficacy to overcoming impediments. Factor loadings, t-values and fit indices showed that the SCT model was fitted to the data. Cronbach's alpha-coefficient ranged from 0.78 to 0.85 and intraclass correlation coefficient from 0.73 to 0.90