Mike Farrar ('PbR to become 'payment for performance' in NHS North West', HSJ 1 February) is right - there is no reason why pay for performance (P4P) can't be introduced into the NHS.

Mike Farrar ('PbR to become 'payment for performance' in NHS North West', HSJ 1 February) is right - there is no reason why pay for performance (P4P) can't be introduced into the NHS.

However, a timely evaluation of the Premier P4P system proposed for North West NHS in the New England Journal of Medicine last week provides little support for the wholesale introduction of payment driven quality improvement initiatives. According to the accompanying editorial if P4P were a clinical intervention it would be regarded as lacking sufficient evidence at this time.

There are several concerns with P4P:

- Evaluations produce conflicting results

- The Premier study design leaves much uncertainty about the accuracy and causes of its results as its authors acknowledge

- Even if the results in the study are accurate it is not clear what, if anything, they mean in terms of patient outcomes

- It is a complex intervention that may have unanticipated consequences.

As others have noted, P4P may encourage organisations to focus on quality improvements and improve their information systems, and for these reasons could be trialled in the NHS. But the NHS already has a variety of mechanisms for promoting quality and it would be important to understand how these interact with P4P.

It would make sense to use the resources available to the NHS - NICE, the Healthcare Commission, the NHS Information Centre, the NHS Institute, and the Centre for Health Economics - to support an evaluated introduction of P4P into secondary care in the NHS.

Ben Toth, Chief Executive, Health Perspectives Ltd