BACKGROUND: Workers' compensation wage replacement data have recently been used to estimate time to return to work (RTW) and the number of work days lost after occupational injury. The degree to which indemnity-based measures reflect self-reported work disability has until now not been studied. METHOD: Kaplan-Meier curves of administrative and self-reported measures of duration of work disability were compared within a sample of 433 low back injury claimants followed up for 1 to 3.7 years. RESULTS: Administrative measures consistently and significantly underestimated the duration of disability when compared to self-reported measures of RTW. The difference between the estimated mean number of work days lost for comparable administrative and self-reported measures ranged from 142 to 334 days. CONCLUSIONS: Number of work days lost after low back injury is substantially underestimated by measures based on the duration of wage replacement benefits. This calls into question the adequacy of indemnity benefits and underscores the need for disability prevention programs.
BACKGROUND: Workers' compensation wage replacement data have recently been used to estimate time to return to work (RTW) and the number of work days lost after occupational injury. The degree to which indemnity-based measures reflect self-reported work disability has until now not been studied. METHOD: Kaplan-Meier curves of administrative and self-reported measures of duration of work disability were compared within a sample of 433 low back injury claimants followed up for 1 to 3.7 years. RESULTS: Administrative measures consistently and significantly underestimated the duration of disability when compared to self-reported measures of RTW. The difference between the estimated mean number of work days lost for comparable administrative and self-reported measures ranged from 142 to 334 days. CONCLUSIONS: Number of work days lost after low back injury is substantially underestimated by measures based on the duration of wage replacement benefits. This calls into question the adequacy of indemnity benefits and underscores the need for disability prevention programs.