Preliminary validation in Spanish of a scale designed to measure motivation in physical education classes: the Perceived Locus of Causality (PLOC) Scale.

The purpose of this paper was to validate the Spanish version of the Perceived Locus of Causality Scale (PLOC; Goudas, Biddle, & Fox, 1994). To achieve this, two studies with samples of 1535 and 400 physical education students, of ages 12 to 17 years, were carried out. The psychometric properties of the PLOC were examined through the following analyses: confirmatory factor analysis, factor invariance, correlation among factors, reliability (Cronbach's alpha), temporal stability (test-retest), and criterion validity. The results partially supported the five-factor structure. This structure was invariant across the two study samples. Correlations among the subscales indicated a simplex pattern, supporting construct validity of the scale. Alpha values over .70 (except for introjected regulation) and high temporal stability (intra-class correlation coefficient = .83 to .90) over a four-week period were obtained. The mastery-approach goal positively predicted self-determined motivation, whereas the performance-avoidance goal predicted it negatively. Future studies should continue to analyze the psychometric properties of the PLOC, as the validation of an instrument should be an ongoing process.