How many people are employed in the public sector? On 18 June the Cabinet Office issued a new set of numbers, the result of a ring-round to Government departments, executive agencies and non-departmental bodies to ask them how many heads are in the head-count.

This is a very odd thing to have done, as public sector employment is already counted by the Office for National Statistics and the latest returns, for the first quarter of 2010, had come out just two days earlier. These are proper statistics, classified as such, while the Cabinet Office almost falls over itself admitting that its own figures are (to use Francis Maude’s phrase) “a bit rough and ready”.

I’ve seldom read a more apologetic press release. The Notes to Editors explains: “These figures are not official statistics ... they have not been reconciled with the ONS figures and where they contradict, it is not an indication that the ONS figures are incorrect. As the figures being published are a scoping exercise it is not expected they will correlate with ONS’ independent quality assured programme.

There’s more. “The figures are neither complete nor validated. The exercise was conducted under a short time frame limiting the time for quality assurance at an organisational level. No further validation was undertaken centrally. Some organisations have not submitted returns in the timeframe available.

“Extreme caution should be exercised when drawing inferences from these figures. In particular, we do not recommend making comparisons between organisations as differences in how organisations have interpreted the definitions of, for example, contingent labour may vary.” This is as close as I’ve ever seen to a Government department admitting its figures are probably rubbish.

It’s certainly not very reassuring to think that the Government may be basing policy on these numbers as it begins the task of cutting public spending in today’s budget, and by implication reducing the public sector head-count.  Why on earth create a set of dodgy figures when there are real figures available? It’s enough to make a statistician weep.

For what it’s worth, the Cabinet office ring-round produced a figure of 640,000 payroll staff in the bodies it rang. In addition there were 20,000 staff classified as contingent labour, who are not on the payroll and may be consultants, some of them. But, in a further apology, the press release admits we don’t know this, there may be double counting, and there’s not always a clear boundary between what could be considered a contracted-out service as opposed to the use of contractors. That’s why the job of counting employees is more than simply asking HR managers to jot the figures on the back of an envelope.

Most people, asked to do this job on a short timeframe (or time frame, the Cabinet Office using both versions in the same sentence, see above) would have simply looked up the latest figures for their department from the ONS tables and sent them in, perhaps with a minor adjustment to add credibility. So let’s make a comparison, exercising “extreme caution”, and see if that might be true.

Take the UK Statistics Authority, an organisation that knows how to count. Its headcount of permanent employees in the ONS tables is 4,020. In the Cabinet Office table, it’s 4,019. Or take the Cabinet Office itself: 1,361 by its own count, 1,290 by ONS.  Or the Serious Fraud Office: 320 by ONS (a 2009 figure), 306 by the Cabinet Office count.

We’re not supposed to compare these figures, but doing so shows that the newly gathered data already exists in a quality-assured form. The only additional information the Cabinet Office may have gathered is in the number of consultants employed, but I suspect that’s also available somewhere in the ONS output, had I the time or skill to extract it. The Cabinet Office figures also include costs broken down by departments.

The Cabinet Office says it won’t be repeating the exercise, but why it was ever carried out at all is a bit of a mystery. Francis Maude, Minister for the Cabinet Office, said: “Until now we’ve only had an incomplete picture of the true numbers of people working for us.” Really? I’m not sure the ONS would take that view.