- BACKGROUND/AIM: Routinely using outcome measures as an integral component of practice has been encouraged for decades yet has not been widely adopted. There are many reasons to measure outcomes yet any positive effect of measurement on our programs or clients has not been substantiated. If the time-consuming nature of outcome measurement is to be encouraged, we need to begin addressing larger questions of the value of outcome measurement on care and outcomes. This cohort study evaluated the impact of routinely administering the Canadian Occupational Performance Measure on client outcomes on a geriatric rehabilitation unit. METHODS: Changes in Functional Independence Measure™ scores between an experimental group (n = 45) that received the routine use of the Canadian Occupational Performance Measure for evaluation/planning versus a historical comparison group (n = 58) that received 'usual' care were analysed using generalised linear modeling. RESULTS: Both groups had significant changes in Functional Independence Measure™ scores over time. Results for differences between groups were inconclusive with a significantly underpowered analysis; however, results suggest that a medium to large effect of this intervention cannot be expected. CONCLUSIONS: Results are significant for the field of routine outcome measurement, suggesting that when adding the Canadian Occupational Performance Measure to routine assessment within an inpatient rehabilitation setting, substantially improved Functional Independence Measure™ score outcomes should not be expected. The value of routine outcome measurement on client outcomes remains largely unexplored. Routinely, using outcome measures requires additional research to determine the specific benefits to our programs and client outcomes.