Reliability and validity of the Japanese version of Job Content Questionnaire: replication and extension in computer company employees.

In order to investigate the reliability and validity of selected scales from the Japanese version of Job Content Questionnaire (JCQ, Karasek 1985), a survey was conducted of 1,126 employees of a computer company in Japan using a questionnaire including 31 items from the JCQ. Ten JCQ scales on psychological and physical demands were examined in 603 male and 84 female respondents. Cronbach's alpha reliability coefficients for nine JCQ scales which consisted of two or more items ranged from 0.66 to 0.90 for males and from 0.64 to 0.88 for females. Item factor analysis for each scale indicated that the first factor explained 50 or more percent of item variation of decision authority, supervisor support, coworker support and Framingham physical exertion in males and females and of psychological demands in females. The skill discretion, decision authority and decision latitude significantly and positively correlated with age, years of employment and years of experience in males (p < 0.05). The decision authority significantly and positively correlated with age and years of experience in females (p < 0.05). Psychological demands, Framingham demand and physical exertion significantly and positively correlated with overtime in males and females (p < 0.05). Skill discretion, decision authority and decision latitude, psychological demands and Framingham demand were lowest in computer equipment operators; physical exertion and Framingham physical exertion were lowest in computer software engineers/technicians. It is suggested that these JCQ scales are reliable and valid instruments for assessing job stressors in computer company employees in Japan.