Evaluation of the introduction of a pay for performance contract for UK family doctors using participant perceptions

In 2004 the UK government introduced a new ‘pay for performance’ element into the contract for family doctors (FDs). Its universal introduction with no pre-intervention data is not atypical of system-wide health reform but poses a considerable evaluation challenge. We derive estimates of its impact based on qualitative perceptions of the treatment effect reported by a sample of participants. We exploit variation in the firstyear achievements of those participants who thought quality had remained the same to generate pre-intervention estimates for those that perceived a change in quality. The average partnership of 4 FDs was paid £74,000 for achieving 982 of the 1,050 quality points available in the first year. Of these, we estimate the mean net gains attributable to the new contract to be less than 4 quality points. These gains were predominantly made on the clinical criteria and were larger for partnerships facing more competition for patients and with markers of higher quality prior to the introduction of the new contract.