Thursday, May 21, 2009

Politicians and journalists, put the statistic down and step away.

A person with a little bit of information is usually a danger to themselves and possibly society.  This is particularly the case at a time when something must be done.

A good example of this is the present scandal on MPs' expenses (does it have an official name yet - "Duck-gate").  A number of people have jumped on some analysis by Mark Reckons, a LibDem blogger, that seems to indicate there is a positive correlation between the size of an MP's electoral majority and the chances that they will abuse the expenses system.  In essence, the more safe an MP feels, the more likely they are to be a crook.

This apparent correlation has led Mark and a number of other people (such as Polly Toynbee and Ben Bradshaw) to suggest that we move away from the First-Pass-The-Post election system.  Their reasoning is that a PR election system would lead to lower majorities for MPs', and according to this correlation, more honest MPs.

Now, the first problem with this is that (I think) the analysis doesn't stand up to scrunity (details of my concerns are here).  Mark has been careful to caveat his statistical conclusions, though I don't think his caveats go far enough.  The caveats, of course, have been ignored by everyone else.

Secondly, even if there is a correlation, it does not mean there is any real or useful link between majorities and honest MPs.  A classic example is the correlation that areas with high level of policing having a high level of crime, leading to the policy conclusion that policing should be reduced as it causes crime.

And finally, what no-one seems to have tried to show is how PR will help, even if the correlation holds.  Though there may be many reasons for PR, tackling MPs expense dodgies seems the flimsest.  Consider:
  • While PR will change the majorities of some MPs, it needn't necessarily lead to the fall in the majorities overall.  You could have some MPs, which after first and second votes, have a larger majority.
  • Some forms of PR can lead to more corruption.  For instance, voters have little ability of getting rid of a hated MP in some forms of close list systems, where that MP heads the list.
  • It would seem from the evidence of the unseating of Neil Hamilton in the 1997 election, and the current mass sacking of tarnished MPs, that the current system can act to get rid of sleazy MPs when the voters have the facts.
So please, before advocating constitutional reform, can we stop and think for one moment.