CIHI's hospital standardized mortality ratio: friend or foe?

Hospital standardized mortality ratios (HSMRs) for acute care hospitals across Canada (excluding Quebec) were released in November 2007 by the Canadian Institute for Health Information. Since the release, some hospitals have undertaken in-depth analyses of their HSMRs to make sense of their results. In this issue of Healthcare Papers, Penfold et al. describe their experiences with the measure, pointing out shortcomings with using such a highly aggregated measure of hospital performance. We echo their concerns with the HSMR and highlight the caveats to interpreting this measure. However, we also point out that, despite its limitations, the HSMR stimulated the authors to probe, on behalf of their institution, factors that may have influenced mortality rates. This probing underlines the merit of HSMR reporting and the types of insights and knowledge that are likely to be gained if other institutions undertake similar evaluations.