Thursday, 19 August 2010

Lies, Damn Lies, and Speed Cameras

I seem to remember writing a post a few short days ago bemoaning the willingness of the BBC to over-interpret some completely unreliable data from Oxfordshire's Safety Camera Partnership.

I may have made a silly mistake. I assumed that the data, although obviously unreliable as it was based on a hopelessly small sample, was true. I assumed that the Safety Camera Partnership was staffed by honest civil servants doing what they genuinely believed to be the best course of action for road safety. I assumed that the SCP staff were not lying spin doctors peddling untruths in order to whip up public sentiment in a desperate attempt to regain their budget and line their pockets at the expense of taxpayers.

My assumptions may have been right. However, consider this. When the local rag asked for the data underlying the claims of rising numbers of speeding drivers, the SCP said that
"those figures were not readily to hand"
which is, of course, odd given that a few days earlier the SCP had issued a press release that relied on them.

The reporters did manage to get hold of them, though, which is even odder when you consider that the figures were "not to hand". In the case of the camera at which the SCP said speeding offences had risen 18%,
speed offences actually fell by four per cent [...] during five days of monitoring since the switch-off on August 1, compared to offences committed between 2008 and 2009.
Very odd indeed.


  1. “As we have always maintained, these remain limited data sets and there is a great deal more study that will need to be undertaken to determine what the increased risk at decommissioned camera sites is.”

    So first they deny lying, then say more data is needed, then make it clear they will not entertain the possibility that there is no increased risk. Maybe even less of a risk.

  2. Yes - no sign of any pre-analysis bias there... Oh, no... :o)

  3. Policy-based evidence again.

  4. Welcome, Richard (and Bucko!).

    Policy-based evidence? Of course - in the minds of these people, evidence is something you collect to support your point, not to work out what your point should be...