Psychometric properties of the French version of the Karasek Job Content Questionnaire: a study of the scales of decision latitude, psychological demands, social support, and physical demands in the GAZEL cohort

Objectives: The objective of this study was to explore the psychometric properties of the French version of the Karasek Job Content Questionnaire (JCQ) for the recommended scales of psychological demands, decision latitude, social support, and physical demands. Internal consistency, factorial validity, and convergent validity were examined in a large occupational cohort of men and women. Methods: This study was based on the GAZEL cohort composed of workers aged 40-50 years for men and 35-50 years for women employed by the French national electric and gas company Electricite De France-Gaz De France (EDF-GDF) in 1989. This cohort has been followed up since 1989 by means of yearly self-administered questionnaires and by the collection of data provided by the company. Results: The study population included the 11,447 GAZEL subjects, 8,277 men and 3,170 women, who were working and who answered the French version of the JCQ in 1997. Cronbach's alpha coefficients higher than 0.65 supported the internal consistency of the JCQ scales and subscales. The results of exploratory factor analysis were consistent with the expected dimensions. Physical demands, supervisor support, and co-worker support were clearly found. However, for decision latitude, 'repetitive work' and 'learn new things' displayed low factor loadings. For psychological demands, low factor loadings were observed for 'conflicting demands', 'wait on others', and 'no exccssive work'. Confirmatory factor analysis supported the instrument construct in six latent factors: psychological demands, skill discretion, decision authority, supervisor support, co-worker support, and physical demands, although the items mentioned earlier displayed low standardized factor loadings. The associations between the JCQ scales and gender, age, educational level, occupational grade, and job satisfaction were explored using analysis of variance and chi-square test, and supported the convergent validity. Conclusion: Although our results of factor analysis could invite the revision of the two scales of decision latitude and psychological demands, this study provided evidence of the validity of the French version of the four JCQ scales of psychological demands, decision latitude, social support, and physical demands among a large population consisting of French working men and women.