ORIGINAL PAPER
Validity test of the IPD-Work consortium approach for creating comparable job strain groups between Job Content Questionnaire and Demand-Control Questionnaire
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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
KEYWORDS
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.