The psychometric properties of Karasek's demand and control scales within a single sector: data from a large teaching hospital.

OBJECTIVE: This paper reviews the psychometric properties of the core components from Karasek's job content questionnaire, the decision latitude and psychological job demands scales.

METHODS: A self-reported survey was administered in 1995 (time 1), 1996 (time 2), and 1997 (time 3) to employees of a large teaching hospital. Analyses for this paper are based on data from the 484 employees who responded at times 1 and 2.

RESULTS: Both scales demonstrated acceptable internal consistency as assessed by item-total correlations and Cronbach's alpha. In confirmatory factor analysis, the two-factor decision latitude model adequately fit the data. However, our findings suggest that a two-factor model may provide an improved fit over the original one-factor demands model, suggesting that this scale may be two distinct subscales. Lastly, the scales demonstrated acceptable discriminant validity.

CONCLUSION: Apart from some guarded uncertainty over what the demands scale may be measuring, overall, the two scales appeared to perform reasonably well in this sample of health care workers.