Estimating the population at risk for Ontario Workplace Safety and Insurance Board-covered injuries or diseases.

Difficulty in quantifying the population at risk for a work-related injury or disease limits the usefulness of workers' compensation data for surveillance. This article presents a method of obtaining estimates of the Ontario Workplace Safety and Insurance Board (OWSIB)- covered workforce using the Canadian Labour Force Survey (LFS). The method involves extracting that class of worker most likely to be insured by the OWSIB and using actual hours worked to estimate full-time equivalents at risk. Compared to population at risk estimates readily available from published tables, the refined crude estimate was 26% lower and ranged from 15 to 79% lower depending on the age group. The percentage decrease from published estimates was generally greater for women compared to men, particularly in the 25 to 39 year age categories. Consequently, the method of deriving population at risk estimates should be considered when comparing rates across sexes, ages, industries or occupations.