Summary Hospital-level Mortality Indicator (SHMI)
The Summary Hospital-level Mortality Indicator (SHMI) reports on mortality at trust level across the NHS in England using a standard and transparent methodology. It is produced and published quarterly as a National Statistic by NHS Digital.
The SHMI is the ratio between the actual number of patients who die following hospitalisation at the trust and the number that would be expected to die on the basis of average England figures, given the characteristics of the patients treated there.
Guidance for users
The SHMI's specification is founded on an open and transparent methodology. We expect that the SHMI will need to be interpreted, understood and also reproduced by different users. Therefore, we have provided detailed specification documents on the construction of the SHMI and accompanying contextual indicators.
The mapping from ICD-10 diagnosis codes to SHMI diagnosis groups which is referenced in the specification is also available, along with further information on the construction of the provider spells dataset which is used in the calculation of the indicator.
SHMI research and development
Reports and further analyses carried out by NHS Digital on the SHMI are published on the SHMI research and development page, along with a methodology development log which contains comments raised on the SHMI methodology and NHS Digital's response to these.
The SHMI Technical Working Group supported and contributed to the technical work associated with the development and construction of the SHMI. Proceedings of the SHMI Technical Working Group are also available on the SHMI research and development page.
The SHMI is subject to continuous review and has been through the Indicator and Methodology Assurance Service process, which is hosted by NHS Digital on behalf of the wider health and social care system.
Following the recommendations from the national review of the Hospital Standardised Mortality Ratio (HSMR), the Department of Health and Social Care commissioned NHS Digital to produce and publish the SHMI. As part of the review, the Department of Health and Social Care also commissioned independent statistical modelling work, which was carried out by the School of Health and Related Research (ScHARR) at the University of Sheffield and their report is available to download below.
We welcome further comments on the SHMI, and suggestions for improvement can be sent to firstname.lastname@example.org.