David Cameron's letter (pdf) to Oxfordshire County Council has been widely criticized, but I fear there's one thing his critics are under-playing.

Cameron wrote:

I would have hoped that Oxfordshire would instead be following the best practice of Conservative councils from across the country in making back-office savings and protecting the frontline.

There's a big omission here. Cameron does not say exactly what "best practice" is - except for proposing asset sales, which as Mr Hudspeth points out (pdf) are "neither legal, nor sustainable in the long-term". Nor did he bother to say in which precise ways Oxfordshire Council was falling short of "best practice."

A Prime Minister who was serious about making efficiency savings would not have been so sloppy. Instead, he would have created a public register of "best practice" by councils around the country. Such a register would have two virtues:

1. Efficiency savings will be, in Sir Dave Brailsford's words, about the aggregation of marginal gains. Countless apparently mundane tweaks to procurement, administration and so on add up significantly. But councils have to know what these are. And they can do so by learning from others. Such a register would collate thousands of dispersed and fragmentary ideas from the 433 UK local authorities.

2. A public available register would bolster councils' incentive to adopt "best practice" as it would allow voters to benchmark their local authority against others.

We know from the work (pdf) of Nick Bloom and John Van Reenen that, in the private sector, there is a "long tail of extremely badly managed firms". I don't know if the same is true for public sector organizations - and nor, judging from the imprecision of his letter, does Mr Cameron. A register of best practice would tell us.

Rick might be right to say that "councils have already made most of the back office savings they can safely get away with". Again, a register would tell us.

I fear that what's going on here is more than mere incompetence, but two other things.

One is cargo cult management. Mr Cameron seems to think that "best practice" can arise magically merely by requesting it. This is not the case. It must be discovered and facilitated. Good leaders, in business or politics, know this.

Secondly, this corroborates my fear that Tory attitudes to spending cuts are putting the cart before the horse. A sensible strategy to cut spending would be one which "efficiency savings" were identified in advance of spending plans. Instead, spending cuts seem to be motivated less by a genuine desire to increase efficiency and more by an asinine macroeconomic policy.

Another thing: Mr Cameron seems to think "best practice" is confined to Conservative councils. This seems to me to be a level of political partisanship which verges on a mental illness.