Hospital Standardized Mortality Ratio

What is Hospital Standardized Mortality Ratio (HSMR)?

The Canadian Institute for Health Information (CIHI) has calculated the HSMR for eligible acute care hospitals and regions in Canada (excluding Quebec). HSMR is an overall quality indicator and measurement tool that compares a hospital’s mortality rate with the overall average rate. It has been used by many hospitals worldwide to assess and analyze mortality rates and to identify areas for improvement.

How is HSMR calculated?

The HSMR is calculated as a ratio of:

The number of (actual) observed deaths    x 100
The number of expected deaths

The HSMR is based on diagnosis groups that account for 80% of all deaths in acute care hospitals, and is adjusted for factors such as: diagnosis group, age, sex, length of stay, admission category, comorbidities, and transfers.

A ratio that is equal to 100 suggests that there is no difference between the hospital’s mortality rate and the average national rate.

A ratio greater than 100 suggests that the hospital’s mortality rate is higher than the average national rate.

A ratio less than 100 suggests that hospital’s mortality rate is lower than the average national rate.