These indicators are designed to accompany the SHMI publication.
Information on the main condition the patient is in hospital for (the primary diagnosis) is used to calculate the expected number of deaths used in the calculation of the SHMI. A high percentage of records with an invalid primary diagnosis may indicate a data quality problem. A high percentage of records with a primary diagnosis which is a symptom or sign may indicate problems with data quality or timely diagnosis of patients, but may also reflect the case-mix of patients or the service model of the trust (e.g. a high level of admissions to acute admissions wards for assessment and stabilisation).
Contextual indicators on the percentage of provider spells with an invalid primary diagnosis and the percentage of provider spells with a primary diagnosis which is a symptom or sign are produced to support the interpretation of the SHMI.
Notes:
1. There is a shortfall in the number of records for Buckinghamshire Healthcare NHS Trust (trust code RXQ), Mid Cheshire Hospitals NHS Foundation Trust (trust code RBT) and Torbay and South Devon NHS Foundation Trust (trust code RA9). Values for these trusts are based on incomplete data and should therefore be interpreted with caution.
2. Due to a problem with the process which links Hospital Episode Statistics (HES) data to the Office for National Statistics (ONS) death registrations data, some in-hospital deaths have been counted as survivals in a small number of trusts. This affects 126 spells in the May 2025 to April 2026 time period for Wirral University Teaching Hospital NHS Foundation Trust (trust code RBL) meaning that the number of observed deaths has been underestimated and so the results for this trust should be interpreted with caution. For the other trusts, the number of affected spells (and hence the impact on the SHMI) is small.
3. 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). In this publication, data are still presented for the two separate organisations. Data will be presented for the new trust at a later date.
4. 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.
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.