The Numbers Game

The London Criminal Justice Board (they of the free mousemats and pens) have a page on their website headed 'Achievements'. They include a graph along with some statistics about Offences Brought to Justice. The graph shows an encouraging upward curve, and we are told that OBtJs have increased by 15% over the last twelve months and that London 'easily' met its target.
These figures are, of course, entirely bogus. On the face of it they seem to show that London's sturdy police force is working more effectively then ever and is beavering away to detect and charge criminals. What they really show is that the target-driven policy of dishing out fixed penalty notices to all and sundry, each of them counted as a Sanction Detection, is driving the figures up. It really is a bit thick to claim that a £40 ticket slapped on a drunken teenager is a detection - it's hardly Hercule Poirot, is it? According to Hansard:-

The Home Office reviews the performance of police forces on the basis of their sanction detection rate. The sanction detection rate is the percentage of crimes for which someone is charged, summonsed, receives a caution or other formal sanction.

Thus, a policeman who has a quiet word with someone, and advises them to calm down and go home wins no brownie points at all, whereas a ticket, or an arrest followed by a caution will push that graph just a little higher. And the crime figures against which the percentage of SDs is calculated are notoriously unreliable anyway, almost to the point of being meaningless.
You can't blame coppers for following the policies of their political masters; that's what they are paid for, after all. Just don't kid yourself that these masses of statistics prove anything about what is really going on on the street.