Like all 'league tables' ever published on any aspect of the NHS, this week's reference costs for surgery have prompted the trusts which find themselves in conspicuous positions to dash for cover. And like all previous league tables, they offer plenty of cover.

For they patently do not compare like with like, the most basic prerequisite for any such exercise to claim validity. So, for example, they reveal that a specialist neurosurgery centre incurs the highest costs, while trusts with a high proportion of more straightforward activity susceptible to day surgery have the lowest costs. Is that kind of information worth the brouhaha which accompanied its release on Monday?

To be fair, the reference costs come liberally hedged around with caveats. Their wide variations may have perfectly innocent explanations, the report admits. They may disguise one-off costs due to restructuring, say. Counting activity and allocating costs are not done consistently between trusts. And despite the use of healthcare resource groups, the results cannot be fully adjusted for differences in casemix. All of which might, you would think, render this entire document pointless. That, of course, is not the message which inevitably ends up in the headlines.

Ministers argue that this information is a manifestation of their commitment to openness in the NHS. Managers left to explain complex concepts to impatient and indignant local newspapers may dismiss it as naming and shaming.

Far be it from us to argue that this information should not be published; the NHS has a long way to go before it can honestly boast of openness. But the service is a long way too from knowing which of these variations in reference costs are acceptable and which are not. It needs time to refine and understand the information and to put it in context alongside data on quality and outcomes. Until that time, both managers and ministers should resist any temptation to make use of it.