These indicators are designed to accompany the SHMI publication.
As well as information on the main condition the patient is in hospital for (the primary diagnosis), the SHMI data contain up to 19 secondary diagnosis codes for other conditions the patient is suffering from. This information is used to calculate the expected number of deaths.
'Depth of coding' is defined as the number of secondary diagnosis codes for each record in the data. A higher mean depth of coding may indicate a higher proportion of patients with multiple conditions and/or comorbidities, but may also be due to differences in coding practices between trusts.
Contextual indicators on the mean depth of coding for elective and non-elective admissions are produced to support the interpretation of the SHMI.
Notes:
1. As of the July 2020 publication, COVID-19 activity has been excluded from the SHMI. The SHMI is not designed for this type of pandemic activity and the statistical modelling used to calculate the SHMI may not be as robust if such activity were included. Activity that is being coded as COVID-19, and therefore excluded, is monitored in the contextual indicator 'Percentage of provider spells with COVID-19 coding' which is part of this publication.
2. Please note that there was a fall in the overall number of spells from March 2020 due to COVID-19 impacting on activity for England and the number has not returned to pre-pandemic levels. Further information at Trust level is available in the contextual indicator ‘Provider spells compared to the pre-pandemic period’ which is part of this publication.
3. There is a shortfall in the number of records for The Princess Alexandra Hospital NHS Trust (trust code RQW), Guy’s and St Thomas’ NHS Foundation Trust (RJ1), King’s College Hospital NHS Foundation Trust (RJZ), and East Lancashire Hospitals NHS Trust (RXR). Values for these trusts are based on incomplete data and should therefore be interpreted with caution.
4. Frimley Health NHS Foundation Trust (trust code RDU) stopped submitting data to the Secondary Uses Service (SUS) during June 2022 and did not start submitting data again until April 2023 due to an issue with their patient records system. This is causing a large shortfall in records and values for this trust should be viewed in the context of this issue.
5. There is a high percentage of invalid diagnosis codes for Chesterfield Royal Hospital NHS Foundation Trust (trust code RFS), Milton Keynes University Hospital NHS Foundation Trust (trust code RD8), West Suffolk NHS Foundation Trust (trust code RGR), and Portsmouth Hospitals University NHS Trust (RHU). Values for these trusts should therefore be interpreted with caution.
6. A number of trusts are now submitting Same Day Emergency Care (SDEC) data to the Emergency Care Data Set (ECDS) rather than the Admitted Patient Care (APC) dataset. The SHMI is calculated using APC data. Removal of SDEC activity from the APC data may impact a trust’s SHMI value and may increase it. More information about this is available in the Background Quality Report.
7. 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.