Citation

Altree-Williams S. J. Health Saf. Res. Pract. 2010; 2(2): 34-40.

Copyright

(Copyright © 2010, Safety Institute of Australia, Publisher LexisNexis Media)

DOI

unavailable

PMID

unavailable

Abstract

Of the two parameters used to document case rates in the national OHS statistics, it is frequency rate (rather than incidence rate) that directly equates to the quantitative injury (safety) risk model in which injury (safety) cases are characterised as discrete events occurring randomly in the continuum of work-time. Incidence rate is the preferred rate measure for disease (health) cases because such outcomes are influenced by both the individual’s occupational exposure profile and their endogenous, societal and non-work exposure characteristics. It is established that the incidence rate parameter may show significant bias (i.e. systematic error) as a measure of disease (health) observed risk and outcome performance because it is independently influenced by the average duty cycle of employees (as well as by risk). Benchmarking the incidence rate parameter eliminates this bias and provides a more accurate measure of observed risk and outcome performance. Importantly, this understanding reduces the OHS outcome data requirement to two variables: cohort case numbers (separated by injury case and disease case) and total cohort work-hours. The natural characteristics of observed risk and outcome performance in relation to OHS are presented with clarifying examples. The distinction between absolute and relative outcome performance is discussed. The value of these concepts (and their quantitative documentation through appropriate frequency and incidence rates) to the continuing challenge to improve OHS performance is emphasised.