Purpose: The original effort-reward imbalance (ERI) questionnaire has been widely used as a measure of occupational stress. The need for brief measurement of psychosocial stress at work has risen. This study examined the psychometric properties of a 16-item short form ERI (S-ERI) questionnaire.
Methods: A cross-sectional study was conducted with a convenience sample of 247 career firefighters in the United States. An internet-based survey contained the S-ERI questionnaire, and assessed perceived health, demographics, and work characteristics. Internal consistency was tested by item-total correlation and Cronbach's α coefficients. Factorial validity was assessed by confirmatory factor analysis (CFA), and criterion validity was examined by testing the S-ERI's association with perceived health, controlling for other factors.
Results: The study participants were primarily young and mid-aged White males (mean age = 42 years, 75% White non-Hispanic, 93% males). The S-ERI questionnaire showed satisfactory internal consistency, with Cronbach α coefficients above 0.80 for all three scales: effort 0.82, reward 0.83, and overcommitment 0.81. CFA showed all the S-ERI components had a good fit (goodness-of-fit index = 0.99, comparative fit index = 0.92, root mean square error of approximation = 0.06). In terms of criterion validity, significantly increased odds ratios (ORs) for perceived health (those indicating they were less healthy) were found in firefighters in the lowest tertile of reward (OR = 7.06, 95% confidence interval [CI]: 2.86-17.43), and highest tertile of overcommitment (OR = 2.29, 95% CI: 1.00-5.22), after controlling for other factors.
Conclusion: The S-ERI questionnaire is a reliable and valid measure to assess occupational stress. We recommend the use of S-ERI as a measure of occupational stress when initiating efforts to improve firefighters' wellness.
Keywords: effort−reward imbalance; firefighter; occupational stress; psychometric properties.
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