Latest results from the patient reported outcome measures (PROMs) scheme released last week by the NHS Information Centre show patients' view of care varies considerably depending on the type of scoring system used.
The government is planning to use PROMs to assess care throughout the NHS, including GP practices and clinical commissioning groups.
GPC deputy chairman Dr Richard Vautrey said: 'We remain very concerned about the use of PROMs in general practice. It is easy to be a popular doctor but much harder to be a good one.'
He added: 'It is not possible to make simplistic assessments about the complex care provided by GPs and the fact that they don't appear to work in limited surgical areas simply underlines why this is a bad idea for general practice.'
In 2010/11, patients returned 171,028 pre-operative and 94,240 post-operative questionnaires. The percentage who felt their condition had improved after a procedure for varicose veins varied from 39.3% to 83.1% between scoring mechanisms. For hip replacement, satisfied patients varied from 59.9% to 95.9%.
It is the second year that PROMs questionnaires have been used. The tests ask substantially different questions. One score asks about five areas of health including mobility and pain, while another only asks for a patient's subjective rating of perceived health for that day, scored out of 100.