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Summary Hospital-level Mortality Indicator

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.

Why are we producing the SHMI?

Following the recommendations from the national review of the Hospital Standardised Mortality Ratio (HSMR), the Department of Health has commissioned NHS Digital to produce and publish the SHMI. As part of the review, the Department of Health 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.

Our commitment to openness and transparency

The documents published here are intended to ensure that the SHMI's specification is founded on a methodology that is completely open and transparent. We expect that the SHMI will need to be interpreted, understood and also reproduced by a range of different users, if necessary. Therefore, we have published a detailed specification document on the construction of the SHMI.

pdf icon Indicator specification: Summary Hospital-level Mortality Indicator methodology [949kb]

xls icon ICD-10 to SHMI diagnosis group lookup table [275kb]

To support the interpretation of the SHMI, various contextual indicators are published alongside it and their specifications are also available to download.

zip icon SHMI contextual indicator specifications [4Mb]

Our commitment to continuous improvement

The SHMI is subject to continuous review and has been through the Indicator Assurance Process, which is hosted by NHS Digital on behalf of the wider health and social care system.

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 support and contribute to the technical work associated with the development and construction of the SHMI. Proceedings of the SHMI Technical Working Group are made publicly available on the SHMI research and development page.

SHMI research and development

We welcome further comments on the SHMI, and suggestions for improvement should be sent to

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