ORIGINAL PAPER
Validity test of the IPD-Work consortium approach for creating comparable job strain groups between Job Content Questionnaire and Demand-Control Questionnaire
Bongkyoo Choi 1, 2, 3  
,  
Sangbaek Ko 1, 4  
,  
 
 
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1
University of California, Irvine, United States of America (Center for Occupational and Environmental Health)
2
University of California, Irvine, United States of America (Program in Public Health)
3
Korea University, Seoul, South Korea (Department of Environmental Health)
4
Yonsei University Wonju College of Medicine, Wonju, Gangwon-do, South Korea (Department of Preventive Medicine)
5
Lund University, Malmö, Sweden (Social Medicine and Global Health)
CORRESPONDING AUTHOR
Bongkyoo Choi   

Center for Occupational and Environmental Health, University of California, Irvine, 100 Theory, Suite 100, Irvine, CA, USA
 
Int J Occup Med Environ Health 2015;28(2):321–333
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ABSTRACT
Objectives: This study aims to test the validity of the IPD-Work Consortium approach for creating comparable job strain groups between the Job Content Questionnaire (JCQ) and the Demand-Control Questionnaire (DCQ). Material and Methods: A random population sample (N = 682) of all middle-aged Malmö males and females was given a questionnaire with the 14-item JCQ and 11-item DCQ for the job control and job demands. The JCQ job control and job demands scores were calculated in 3 different ways: using the 14-item JCQ standard scale formulas (method 1); dropping 3 job control items and using the 11-item JCQ standard scale formulas with additional scale weights (method 2); and the approach of the IPD Group (method 3), dropping 3 job control items, but using the simple 11-item summation-based scale formulas. The high job strain was defined as a combination of high demands and low control. Results: Between the 2 questionnaires, false negatives for the high job strain were much greater than false positives (37–49% vs. 7–13%). When the method 3 was applied, the sensitivity of the JCQ for the high job strain against the DCQ was lowest (0.51 vs. 0.60–0.63 when the methods 1 and 2 were applied), although the specificity was highest (0.93 vs. 0.87–0.89 when the methods 1 and 2 were applied). The prevalence of the high job strain with the JCQ (the method 3 was applied) was considerably lower (4–7%) than with the JCQ (the methods 1 and 2 were applied) and the DCQ. The number of congruent cases for the high job strain between the 2 questionnaires was smallest when the method 3 was applied. Conclusions: The IPD-Work Consortium approach showed 2 major weaknesses to be used for epidemiological studies on the high job strain and health outcomes as compared to the standard JCQ methods: the greater misclassification of the high job strain and lower prevalence of the high job strain.
eISSN:1896-494X
ISSN:1232-1087