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Summary Hospital-level Mortality Indicator (SHMI) now supported by interactive resources

*Regional statistics are included within this report

The Summary Hospital-level Mortality Indicator (SHMI) - Deaths associated with hospitilisation, England, April 2016 - March 2017: annual report is published today by NHS Digital.

Each SHMI publication2 is supported by the following resources which aim to provide a more user-friendly and accessible introduction to this topic:

  • A one page summary of the key findings

  • A new interactive data visualisation

  • Data downloads

  • A background quality report

These are available to download from

The new interactive data visualisation, using the latest SHMI data, includes:

  • A map of the trust level data
  • Contextual indicators on various topics including deprivation and the percentage of deaths that occurred during a patient's stay in hospital (and not in the 30 day period after discharge)
  • A breakdown of the data by diagnosis group which can highlight the specific clinical areas which have the most impact on the value of a trust's SHMI

The SHMI reports on mortality at trust level3 across the NHS in England. It 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.

It covers all deaths reported of patients who were admitted to non-specialist acute trusts4 in England and either die while in hospital or within 30 days of discharge. The expected number of deaths is calculated from statistical models derived to estimate the risk of mortality based on the characteristics of the patients (including the condition the patient was in hospital for5, other underlying conditions the patient suffered from, age, gender and method of admission to hospital).

The SHMI can be used by hospital trusts to compare their mortality outcomes to the national baseline. However, it should not be used to directly compare mortality outcomes between trusts and it is inappropriate to rank trusts according to their SHMI.

Where a trust has an "as expected" SHMI this means the difference between the number of observed and expected deaths is not statistically significant according to the methodology.  A "higher than expected" SHMI should be viewed as a "smoke alarm" which requires further investigation by the trust. Similarly, an "as expected" or "lower than expected" SHMI should not immediately be interpreted as indicating satisfactory or good performance.

The SHMI includes admitted patients for all clinical areas within a trust and it is possible that mortality rates differ across these areas. For this reason, we advise all trusts to investigate their SHMI data in detail using the data broken down by diagnosis group, regardless of whether their SHMI is categorised as "higher than expected", "as expected" or "lower than expected".

The difference between the number of observed deaths and the number of expected deaths cannot be interpreted as the number of avoidable deaths for the trust. Whether or not a death could have been prevented can only be investigated by a detailed case-note review.

Read the full report at:


Notes to editors

  1. NHS Digital is the national information and technology provider for the health and care system. Our team of information analysis, technology and project management experts create, deliver and manage the crucial digital systems, services, products and standards upon which health and care professionals depend. During the 2015/16 financial year, NHS Digital published 294 statistical reports. Our vision is to harness the power of information and technology to make health and care better.

  2. The SHMI is published on a quarterly basis and a more detailed report is included as part of the September release which covers the latest financial year of data.

  3. The SHMI is currently reported at trust level rather than site (hospital) level because of concerns around the accuracy of data on site of treatment in the Hospital Episode Statistics (HES) dataset. NHS Digital will continue to review the feasibility of reporting the SHMI at site level as part of the longer term development of the indicator.

  4. Specialist trusts, mental health trusts, community trusts and independent sector providers are excluded from the SHMI because there are important differences in the case-mix of patients treated there compared to non-specialist acute trusts and the SHMI has not been designed for these types of trusts. Integrated trusts which provide both acute and community services are included in the SHMI.

  5. No adjustment is made for the severity of the condition, as this information is not captured in the Hospital Episode Statistics (HES) dataset upon which the SHMI is based. This means that if a trust treats a high (or low) proportion of seriously ill patients with a particular condition compared to other trusts, the statistical models used to estimate the expected number of deaths will not take account of this.

  6. For media enquiries, please contact or telephone 0300 30 33 888.