The Audit Commission's exposure of a high error rate in clinical coding has an impact far beyond payment by results.

As the commission itself highlights, this is not a bean-counter's obsession with how money is shunted round the system; coding errors mean commissioners are making decisions based on flawed information about what clinical work is being performed.

For such a complex system it is amazing that the explanation is so asinine - case notes are either missing or illegible.

HSJ has highlighted before the scale of missing case notes, while the illegibility of doctors' handwriting is the stuff of NHS legend. If coders cannot get hold of usable notes, it is a certain bet that clinicians are making errors for precisely the same reasons.

The Audit Commission study was intended as an audit of payment by results. What it has revealed affects both commissioning and patient safety.