Thursday, 7 May 2009

DNA database

written on another thread by Loftwork.

The argument is always that since a genetic identifier allows the police to establish identity so easily we must keep as much data as possible to avoid the chance of missing a dangerous criminal. This is always trotted out in emotive cases - child abuse, rape, granny-mugging etc.

The principle is in fact the same as the justification for torture: 'we need to do it because it might prevent a terrorist blowing up London'. It rests on the notion that one can strike a balance between a routine but less significant erosion of personal rights and an extreme and terrifying but remote possibility.

The reason that governments manage to make the case so successfully is that human beings are very poor risk assessors. We are biologically wired to respond to severe threats but not to routine threats. Severe threats, no matter how unlikely, provoke a primitive hind-brain Thalamic response: fight or flight. This is illogical - a known threat which kills thousands is routinely ignored, a drastic risk which kills nobody provokes demands for action at any price.

Politicians of course instinctively know how to manipulate this. If there's a problem and logic is against you, simply ramp up the threat level. Logical opposition vanishes as the Noradrenalin kicks in. Can't find a terrorist threat? Put tanks around Heathrow.

So for those who prefer to know who is trying to manipulate them, the first step is to find the fear merchants.

Jac Smith is a fear merchant. ID databases are grossly overhyped but a cool, logical assessment woud be contrary to nulabour political will, so the fear factor will now be spun to a froth.

DNA evidence is nothing new. It is part of a range of techniques which allow identification including fingerprinting, facial recognition, tests for chemical and material transfer etc. etc. In other words, DNA is an investigative tool, not a total solution. It may be just as important that a perpetrator leaves a bit of fabric or a chemical smudge - without police work nothing will happen.

The problem with universal DNA is that it is a probability-based tool so if the sample quality does not give an optimal result or the size of the database is large, the probability of a false positive increases toward unity. And its sensitivity also makes it prone to contamination in a way fingerprints were not. DNA found at a crime site is a starting point for investigation, not its conclusion. Whether the case is brought to successful conclusion is very much a matter of competent policing, as always.

It is therefore fatuous to demand that there be an immense DNA database to avoid the possibility of future crime. The investment might much more profitably be made in improving the workload of parole officers or investing in more programmes to get offenders off drugs or back into work, or just to put policemen back on the street and in local stations instead of in 'fast response' units 20 miles away.

The fact is that this database contributes to a society in which everyone is a criminal, in which criminals no longer have any possibility of 'spent' convictions, in which being suspected of a crime is the same as being guilty of a crime. Fundamentally, it is a society based on the idea that people never change. For a Christian nation that is a sad state of affairs. It is also a sure route to increasing crime, and of course criminals will take strenuous steps to avoid leaving forensic evidence while the innocent will not.

But that would be a logical response. The political will is to have a big, expensive, bureaucratic, unreliable database which involves paying some US contractor billions of pounds. Now watch the fear factor as ministers spin the usual out-of-context war stories and dodgy statistics, again. With nulabour it never stops.

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