This publication was updated on 9th August 2024. Data for Royal Surrey County Hospital NHS Foundation Trust (trust code RA2) has been suppressed from publication. This trust had submitted in error a high percentage of records with no secondary care diagnosis codes, this has made their SHMI values highly misleading. They have corrected the data at source, and this is expected to be reflected in the November SHMI publication.
The SHMI methodology uses 144 statistical models, each corresponding to a different diagnosis group. Each of these models is constructed using a 3 year dataset and includes the following risk-adjustment variables: age, gender, method and month of admission, Charlson comorbidity index, year index and birthweight (for perinatal diagnosis groups only). The adjustment for the Charlson comorbidity index is not included for the diagnosis group containing activity with an invalid primary diagnosis.
Statistics relating to the model fit for each of the 144 statistical models (model fit statistics) and model coefficients (model predict statistics) are published for the purposes of transparency. Details of the statistics provided in each of the files are available in the 'SHMI statistical model data definitions' file.
Notes:
1. Data for Royal Surrey County Hospital NHS Foundation Trust (trust code RA2) has been suppressed from publication. This trust had submitted in error a high percentage of records with no secondary care diagnosis codes, this has made their SHMI values highly misleading.
2. Further information on data quality can be found in the SHMI background quality report, which can be downloaded from the 'Resources' section of the publication page.