Hospital Standardised Mortality Ratios (HSMRs) are one among many tools for quality improvement in hospitals. The measure compares the observed number of deaths in a hospital with the number predicted adjusting for a range of known risk factors.

  • Every District Health Board (DHB) and hospital is different in the patients it sees – so HSMRs take factors like age, gender and clinical conditions into account. Every DHB will also be different in how its services are organised.
  • It is important HSMRs take these differences into account because they can affect the results, but have nothing to do with actual quality of care. However, these adjustments can never be made perfect and some differences may be due to other factors.
  • HSMRs will best be used as an indicator of where further investigation may be beneficial.
  • HSMRs should never be used to rank hospitals against each other, to draw simplistic conclusions about quality of care, or be interpreted as ‘avoidable deaths’.
  • New Zealand overall has a declining HSMR over time. This trend is also observed in comparable countries such as the United Kingdom and Canada.
  • It is important HSMRs as used in New Zealand continue to be fit for purpose. That is why the results will continue to be reviewed by the Ministry of Health, the Commission and the DHBs as part of the wider quality improvement package.

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Last updated 29/09/2015