Regional Differences in Time Off Work After Injury: A Comparison of Australian States and Territories Within A Single Workers' Compensation System.

Purpose Time off work after workplace injury varies by compensation system. While often attributed to features of the compensation system, unaccounted regional factors may drive much of the effect. In this study, we compare disability durations by state and territory of residence within a single national workers' compensation system. Large differences would indicate that factors other than compensation system settings are responsible for system effects observed in previous studies. Methods We applied crude and adjusted Cox proportional hazards models to compare disability durations by state and territory of residence. Confounders included factors known to influence disability duration. Durations were left-censored at two weeks and right-censored at 104 weeks. Results We analysed N = 31,641 claims. In both crude and adjusted models, three of the seven states and territories significantly differed from the reference group, New South Wales. However, two of the three were different between crude and adjusted models. Regional effects were relatively small compared to other factors including insurer type, age, and type of injury. Conclusions Regional factors influence disability duration, which persist with adjustment for demographic, work, insurer type, and injury confounders. However, the effects are inconsistently significant and fairly small, especially when compared to the effect of confounders and system effects found in previous studies. Regional factors likely only account for a small share of the difference in disability duration between compensation systems.