The case-mix adjustment for the national Patient Reported Outcome Measures (PROMs) programme has been published. Separate adjustments are made for each of the outcome measures for each of the four elective procedures: groin hernia surgery; varicose vein repair; hip replacement; and knee replacement.
PROMs data has been routinely collected for these elective procedures since April 2009. The Health and Social Care Information Centre publishes a range of statistics that is derived from the data. Comparing unadjusted average scores between providers can be misleading as the patient profiles that one provider treats may be different to the patient profile at another provider.
In order to make comparisons meaningful, a method is required to adjust for these different profiles. The Department of Health has developed a general case-mix adjustment methodology and specific adjustments for each outcome measure, for each procedure. These adjustments take account of variations in patient characteristics and other factors that are beyond the direct control of providers. This enables more accurate comparisons between the average scores of different providers.
See Patient Reported Outcome Measures in England: The case-mix adjustment methodology