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Occupational Mortality

Environmental Health

  1. Michael J. Symons

Published Online: 15 SEP 2006

DOI: 10.1002/9780470057339.vao002

Encyclopedia of Environmetrics

Encyclopedia of Environmetrics

How to Cite

Symons, M. J. 2006. Occupational Mortality. Encyclopedia of Environmetrics. 4.

Author Information

  1. University of North Carolina, NC, USA

Publication History

  1. Published Online: 15 SEP 2006


In studies of mortality of industrial workers, statistical options are limited when: (1) only a few deaths are observed; (2) exposure information at the workplace is nonexistent; (3) personal concomitant exposure data are not available. With none, some, or all of these limitations, the standardized mortality ratio (SMR) is the most frequently used statistic for occupational and environmental cohorts. The SMR is the total number of observed events, O, divided by the total number expected events, E, for those under study. The SMR, as a one-dimensional summary statistic, is both attractive and limited in scope. It is widely used in mortality studies of industrial populations, serving to screen for excess causes of death and to test for an excess of a specific cause of mortality. A variety of study designs – commonly, proportional mortality, cohort mortality, and case-control studies – are utilized in the further investigation of hypotheses generated or for more confirmatory tests of results from previous analyses.