Do drug-free workplace programs prevent occupational injuries? Evidence from Washington State

Objective. To evaluate the effect of a publicly sponsored drug-free workplace program on reducing the risk of occupational injuries. Data Sources. Workers' compensation claims data from the Washington State Department of Labor and Industries covering the period 1994 through 2000 and work-hours data reported by employers served as the data sources for the analysis. Study Design. We used a pre-post design with a nonequivalent comparison group to assess the impact of the intervention on injury risk, measured in terms of differences in injury incidence rates. Two hundred and sixty-one companies that enrolled in the drug-free workplace program during the latter half of 1996 were compared with approximately 20,500 nonintervention companies. We tested autoregressive, integrated moving-average (ARIMA) models to assess the robustness of our findings. Principal Findings. The drug-free workplace intervention was associated (p<.05) with a statistically significant decrease in injury rates for three industry groups: construction, manufacturing, and services. It was associated (p<.05) with a reduction in the incidence rate of more serious injuries involving four or more days of lost work time for two industry groups: construction and services. The ARIMA analysis supported these findings. Conclusions. The drug-free workplace program we studied was associated with a selective, industry-specific preventive effect. The strongest evidence of an intervention effect was for the construction industry. Estimated net cost savings for this industry were positive though small in magnitude.