For some reason I still feel some kind of duty to write corrective letters to papers I read. Probably a waste of time, but here goes, anyway:
As you point out in your article (May 6th), the debate on speed cameras in Britain has been surprisingly controversial, and has seen much abuse of statistics. The claims made by the anti-cameras lobby in particular explore a rich vein of nonsense which even numerically-challenged British tabloids wisely avoid.
But the statement that `deaths and injuries drop on average by 35%' where cameras are installed is also misleading. As you state, cameras are installed in locations where above-average numbers of accidents have occured. All else being equal, a period in which an above-average number of serious accidents occur at a site is very likely to be followed by a period in which fewer accidents occur, whether or not a camera is installed there.
This effect -- known to statistics as `regression to the mean' -- is well-known and widely understood. But sadly it is rarely addressed properly in studies of speed camera effectiveness. Without controlled trials free from such bias, we do not yet know how effective speed cameras really are.
The very controversy of speed cameras is a cost that should be weighed up when making road safety policy. However effective, cameras are unpopular, and they sour the usually good relationship between citizens and the police. Without good data on the effects of cameras, it is not possible soberly to assess the costs and benefits of using them.
So then, that Iraq, eh? We've sodded that up right bad, haven't we?
I supported the war -- just -- because the general idea of using military force to get rid of dictators, when circumstances permit, is appealing, and maintaining the alliance between the United States and Britain is probably worth its price too. But more importantly, it had never occurred to me that Britain and the United States could invade a country thousands of miles away with the intention of destroying its government and have no plan at all for what to do next.
(As an aside, whatever the government's publicity material said, nobody sensible really believed that Iraq had chemical, biological or nuclear weapons in 2003. And I should remind you that, should you now be moved to say something about the threat of `weapons of mass destruction', you are a priori not sensible, for reasons I needn't repeat. Neither did the war against Iraq have anything to do with `terrorism' in the September 11th sense, however much the United States is keen to define local Iraqi insurgencies as `terrorism'.)
My anti-war friends have typically responded to my surprise about the cack-handedness of Coalition plans for post-war Iraq by saying, roughly, ``Of course they had no idea what to do next -- what did you expect?''
This time round it turns out that they were correct. However, I have a horrible feeling that many of these people would have said the same about almost any exercise of military force. It's just a pity that in the two most recent cases -- Afghanistan and Iraq -- they have turned out to be correct. Nobody asks them about Sierra Leone or the Falklands.
Anyway, I was going to write a long rant about Iraq, but the more I think about it the more I get angry about the use of language in arguments about the war. So, instead, I present,
Right, that's enough Newspeak for now. Any other suggestions? Stick 'em in the comments, please.
Since I haven't written anything here for a bit, some random updates. Chris Brooke encourages us to classify things as to whether they're splendid, meaning `coherent, and I approve'; rubbish, meaning, `coherent, and I disapprove'; or nonsense, meaning `incoherent'. So in that vein, I bring you:
Many things, but the one that's in my mind right now is news that the author of the `Sasser' Microsoft Windows virus has been arrested. (And there was much ignorant rejoicing in the press.) Two comments:
Firstly, these things are really getting out of hand; on Wednesday I was delayed by about two hours on a simple journey from Reading to London by a `signalling fault' at Slough; apparently the signalling on that part of the railway is run on Windows NT. Coincidence? You decide. Why are people building critical infrastructure on this rubbish?
Secondly, there is of course nothing wrong with writing a virus -- that's a simple free-speech issue. There is something wrong with releasing a virus. The press need to emphasise this.
(Sorry, no graph or holiday photos this time. Also, thanks to Tom for correcting a typo.)
This is all done with wwwitter.
Copyright (c) Chris Lightfoot; available under a Creative Commons License. Comments, if any, copyright (c) contributors and available under the same license.