Effects of personality on overtime work: a cross-sectional pilot study among Japanese white-collar workers

BACKGROUND: As detailed associations between personality and long work hours are unclear, we assessed associations between personality dimensions and overtime work among Japanese white-collar workers. METHODS: From records of hours worked over 12 months by 267 office workers in an organization within the service industry, average overtime work hours per month and occurrence of excessive overtime was determined for each worker. Excessive overtime was defined as > 45 overtime work hours per month for at least one month. Responses to a questionnaire assessing socio-demographic and workplace-related factors and the Big Five personality test were analyzed. Associations between personality factors and overtime work were assessed by multivariate logistic regression analysis. RESULTS: Low Extraversion was associated with excessive overtime work (OR 2.02, 95%CI 1.02 – 4.02, P = 0.04). CONCLUSIONS: It is suggested that workers with low Extraversion can’t share work when busy to avoid excessive overtime. Personality factors should be considered in studies evaluating work time. Moreover, strengthening communication among workers with low Extraversion may reduce excessive overtime work and associated health problems.