Int J Environ Res Public Health. 2015 Apr 8;12(4):3889-902. doi: 10.3390/ijerph120403889.

Job exposure matrix for electric shock risks with their uncertainties.

Vergara XP¹, Fischer HJ², Yost M³, Silva M⁴, Lombardi DA⁵, Kheifets L⁶.

Author information

1: Electric Power Research Institute, Environment Sector, Palo Alto, CA 94304, USA. xvergara@epri.com.
2: UCLA Fielding School of Public Health, Department of Biostatistics, Los Angeles, CA 90024, USA. Heidi.j.fischer@gmail.com.
3: Department of Environmental and Occupational Health Sciences, University of Washington School of Public Health, Seattle, WA 98195, USA. airion@uw.edu.
4: Enertech Consultants, Campbell, CA 95008, USA. msilva@enertech.net.
5: Center for Injury Epidemiology, Liberty Mutual Research Institute for Safety, Hopkinton, MA 07418, USA. David.Lombardi@libertymutual.com.
6: UCLA Fielding School of Public Health, Department of Epidemiology, Los Angeles, CA 90024, USA. kheifets@ucla.edu.

Abstract

We present an update to an electric shock job exposure matrix (JEM) that assigned ordinal electric shocks exposure for 501 occupational titles based on electric shocks and electrocutions from two available data sources and expert judgment. Using formal expert elicitation and starting with data on electric injury, we arrive at a consensus-based JEM. In our new JEM, we quantify exposures by adding three new dimensions: (1) the elicited median proportion; (2) the elicited 25th percentile; and (3) and the elicited 75th percentile of those experiencing occupational electric shocks in a working lifetime. We construct the relative interquartile range (rIQR) based on uncertainty interval and the median. Finally, we describe overall results, highlight examples demonstrating the impact of cut point selection on exposure assignment, and evaluate potential impacts of such selection on epidemiologic studies of the electric work environment. In conclusion, novel methods allowed for consistent exposure estimates that move from qualitative to quantitative measures in this population-based JEM. Overlapping ranges of median exposure in various categories reflect our limited knowledge about this exposure.