In defence of the hospital standardized mortality ratio.

This commentary addresses many of the points made by Penfold and colleagues in the lead article of this issue of Healthcare Papers, including the relationships between hospital standardized mortality ratios (HSMRs) and adverse event reporting, hospital policy and discharge rates. It also discusses what the HSMR is intended to measure, the various analyses and cumulative sum statistic data that my colleagues and I provide to hospitals, interpretation of the results and the inclusion or exclusion of patients receiving comfort or palliative care. It should be noted that my colleagues and I still have the attitude that if anyone can make improvements in our methodologies, we are happy to adopt these improvements as long as they are statistically sound. We feel strongly that if a hospital has a high HSMR, then further investigation is merited to exclude or identify quality-of-care issues; this approach can result in a useful insight into mortality at the institution, which can be associated with a decrease in mortality.