Summary Hospital-level Mortality Indicator (SHMI)

What is the Summary Hospital-level Mortality Indicator (SHMI)?

SHMI is a hospital-level indicator which reports mortality at trust level across the NHS in England using standard and transparent methodology. This indicator is being produced and published quarterly by the Health and Social Care Information Centre with the first publication as an experimental Official Statistic in October 2011.

Why are we producing the SHMI?

Following the recommendations of the Hospital Standardised Mortality Ratios (HSMR) Review, the Department of Health committed to implementing the SHMI as the single hospital-level indicator for the NHS. In addition to the work carried out 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.

The Health and Social Care Information Centre were commissioned to proceed with the development of the SHMI. We are grateful to all those who have contributed to the development and the debate of this new indicator.

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.

Our commitment to continuous improvement

Like all indicators managed by the Health and Social Care Information Centre, the SHMI will be subject to continuous review, using our Indicator Assurance Process. Outputs from these reviews will be reported to the National Quality Board, and will be available on our website.

Some of the important changes which have been made to date include:

  • Increasing the robustness of the logistic regression models by using three years of past data to build the models rather than one year
  • Inclusion of an additional field (YEAR_INDEX) to facilitate case-mix adjustment
  • Updated Risk Modelling specifications to include logistic regression options for model convergence
  • Removal of gender specific diagnosis groups as it is no longer required
  • Exclusion of regular night attenders from the dataset for consistency with excluding regular attenders
  • Specify reference category as first category for all classification/case-mix variables for risk model
  • Updated the SHMI banding requirements to report on one banding: 95% random effects model control limits for over-dispersion.

We welcome further comments on the SHMI, and any suggestions for improvement should be sent to clinical.indicators@ic.nhs.uk.

Further information on SHMI methodology