Developing a tool for identifying high-risk employers for inspection

Workers' Compensation Board (WCB) data and other information are sometimes used to calculate an 'Occupational Health and Safety (OHS) index' as a way of identifying businesses considered 'high risk' to be inspected as part of enforcement work. However, no evidence on the validity of this index exists.

To evaluate the performance of the Alberta OHS index, a 'score' based largely on WCB claims data, and to see if an index calculated using different information could perform better.

Data from the Alberta Compliance Management Information System database, 2011-2015, and WCB claim database, 2007-2014, were retrieved. Issuing 'stop work' or 'stop use' orders in inspections was defined as a proxy of high-risk outcome. The performance of the current and a modified OHS index were assessed using receiver operating characteristics (ROC) and regression analyses.

In large employers, neither the current nor the modified OHS index was particularly effective in identifying 'high risk' employers with the area under the ROC curve (AROC) of 0.55 (95% confidence interval [CI] 0.52-0.57; P < 0.001) and 0.59 (95% CI 0.57-0.62; P < 0.001), respectively. In small employers, neither index seemed very effective with an AROC of 0.54 (95% CI 0.53-0.56; P < 0.001) and 0.55 (95% CI 0.53-0.56; P < 0.001), respectively. These results were consistent in subgroup analyses of assignments without specific initiatives, both in large and small employers.

Neither the current nor a modified OHS index seemed to effectively identify high-risk employers. Heterogeneous results in large and small employers suggest that approaches to different-sized employers are appropriate.