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. It includes deaths which occurred in hospital and deaths which occurred outside of hospital within 30 days (inclusive) of discharge.
The SHMI gives an indication for each non-specialist acute NHS trust in England whether the observed number of deaths within 30 days of discharge from hospital was 'higher than expected' (SHMI banding=1), 'as expected' (SHMI banding=2) or 'lower than expected' (SHMI banding=3) when compared to the national baseline.
Trusts may be located at multiple sites and may be responsible for 1 or more hospitals. A breakdown of the data by site of treatment is also provided.
The SHMI is composed of 144 different diagnosis groups and these are aggregated to calculate the overall SHMI value for each trust. The number of finished provider spells, observed deaths and expected deaths at diagnosis group level for each trust is available in the SHMI diagnosis group breakdown files. For a subset of diagnosis groups, an indication of whether the observed number of deaths within 30 days of discharge from hospital was 'higher than expected', 'as expected' or 'lower than expected' when compared to the national baseline is also provided.
Details of the 144 diagnosis groups can be found in Appendix A of the SHMI specification.
Notes:
1. There is a shortfall in the number of records for Torbay and South Devon NHS Foundation Trust (trust code RA9) and York and Scarborough Teaching Hospitals NHS Foundation Trust (trust code RCB). Values for these trusts are based on incomplete data and should therefore be interpreted with caution.
2. There is a high percentage of invalid diagnosis codes for Blackpool Teaching Hospitals NHS Foundation Trust (trust code RXL), Buckinghamshire Healthcare NHS Trust (trust code RXQ), County Durham and Darlington NHS Foundation Trust (trust code RXP), Portsmouth Hospitals University NHS Trust (trust code RHU), The Princess Alexandra Hospital NHS Trust (trust code RQW), University Hospitals Birmingham NHS Foundation Trust (trust code RRK) and West Suffolk NHS Foundation Trust (trust code RGR). Values for these trusts should therefore be interpreted with caution.
3. There are variations between trusts in the recording of same day emergency care (SDEC). Where trusts are submitting SDEC activity as part of the Outpatient dataset or Emergency Care Data Set (ECDS) rather than the Admitted Patient Care (APC) dataset or are recording this activity as day cases within the APC data, these records will not be included in the SHMI. Trusts with SDEC activity removed from the SHMI data have seen an increase in their SHMI value. As all trusts are expected to transition to recording SDEC activity as admitted patients, the data will become more comparable over time and the impact on the SHMI will reduce.
4. On 1st July 2026, North Bristol NHS Trust (trust code RVJ) was acquired by University Hospitals Bristol and Weston NHS Foundation Trust (trust code RA7). The new organisation is called Bristol NHS Foundation Trust (trust code RA7). The new organisation structure is reflected from this publication onwards.
5. Further information on data quality can be found in the SHMI background quality report, which can be downloaded from the 'Resources' section of this page.