The Carr-Hill formula is the formula that is applied to calculate the Global Sum payments for essential and some additional services. This allows payments to be made based upon the cost of providing primary care services for a given population and their respective needs.
The formula takes account of the following variables
Patient age and sex
Additional needs of patients
Staff market forces factor
Each adjustment within the formula generates a separate practice index which allows one to compare the practice score with an adjustment to the national average. Once all of these indices have been applied, this creates a practice weighting.