Both Anthony and Francis argued, in reference to my comments on Tory `bed blockers' and claims made about them that, rather than analysing the data in terms of the age of the individual MPs, I should have used the length of their service in Parliament. In fact, this was what I was originally intending to do, but I couldn't find a good reference which collated the lengths of service of the various MPs; I assumed that their age would be a reasonable proxy. Since I wrote that, Anthony has very kindly complied with my suggestion and provided me with a table of the relevant data, for which gift many thanks are due.
It turns out that (as you'd expect), age and length of service of Tory MPs are pretty well-correlated: (this and later plots ignore various special cases -- speakers, ill MPs and outliers)
but treating the data in terms of length of service does change the results slightly. While there are no significant correlations between MP ages and their performance on the indicators for which I have data, there are with length of service. In particular, both the number of written questions asked and attendance at divisions are inversely correlated with length of service -- that is, MPs who've been in the Commons longer ask fewer questions and vote less often:
(Slightly surprisingly, although the plot -- not shown -- looks convincing, it turns out that there's no significant variation of Fax Your MP response rate with length of service.)
There's not a whole lot to say about this, really. It makes the Torygraph's story a little more plausible, though I'd be cautious about broad-brush use of these indicators. Anthony suggested in email that I see whether it makes any difference whether an MP has served several disconnected stretches or one continuous term; from what I've looked at, it doesn't. If you want a causal theory to inform these vague statistical stumblings, it would be as well to start with the theory (expounded, I think, in Yes, Minister, though I can't find the quote at the moment) that a typical government consists of three-hundred-and-fifty-odd MPs. About a hundred will be too old to be Ministers; about a hundred will be too young; this leaves about a hundred and fifty to fill about a hundred Ministerial posts.
Some of these will be too useless for the job, leaving the government with rather little choice in matters. As MPs age, they risk passing from `eligible' to `elderly', or fucking up badly enough that they become `useless'. (In Matthew Parris's autobiography, he recalls being called to one side by a whip and told that, had he not forgotten to vote in an important division, he would probably have achieved office of some sort; as it was, he was left to languish on the back benches....) As MPs carry on through their Parliamentary careers, with the prospect of high office receding, the incentives to attend divisions, speak and hope to be noticed, and ask endless written questions with the hope of uncovering hidden Governmental scandal must recede with it.
Which is a plausible enough theory if you like that sort of thing. I'm sure if the correlation had come out the other way -- it's hardly striking, after all -- I could have come up with something equally plausible-sounding about the loyalty and work ethic of the long-serving, or some other such nonsense.
Comments
Posted by Francis Irving, Tuesday, 3 August 2004 07:50 (link):
I should mention that the "number of written questions asked" is actually the number asked that have been answered. (I really need to sort out how to describe this different in a few words on TheyWorkForYou.com's MP page)
So it is possible that older MPs ask tougher questions which the government is more likely to not want to answer.
Posted by Francis Irving, Tuesday, 3 August 2004 07:55 (link):
Yes, I'm increasingly of the opinion that statistics are fairly useless for this sort of thing. You can learn a lot more from talking to MPs and getting to know them, or reading biographies, or watching Yes Minister. Not that statistics are useless, you can learn something about speed cameras for instance. Any idea if the Tories latest policy on them is going to use the statistics properly, or they're just going to shut down all the cameras which for some reason haven't regressed to the mean?
Posted by Chris Lightfoot, Tuesday, 3 August 2004 09:05 (link):
Well, really you need to start with a theory, use it to form a hypothesis, and then move on to the statistics. Starting half-way through with a hypothesis (``longer-serving Tories are more useless'') might be convincing if there were some really striking correlations -- and might tell you which MPs to interview if you really wanted to understand what was going on -- but otherwise isn't that helpful. But, as so often, in my last piece I was just arguing that someone else -- in that case, the Telegraph -- was wrong, which requires much less work. This latest exercise says that they might not be (completely) wrong, but it's not really evidence that they're actually right.
God knows. They're apparently going to review `every speed limit' and `every camera', which isn't exactly promising. They're promising an `independent investigation of every speed camera', which strongly suggests that they Just Don't Understand. The chances of someone actually sorting it out (by doing a random controlled trial) or somehow showing that the demonstrable effects of cameras -- hidden cameras are now known to reduce vehicle speeds significantly -- reduce accidents seem fairly remote to me.
Though there were some mutterings about the Tories decreasing speed limits in suburban areas and increasing them on motorways, both of which seem sensible to me. If you believe that the Conservatives are the party which believes in properly balancing the interests of police and policed (and god alone knows we need a party which believes that, now that Blunkett is running the other one's law-and-order policy) then a little bit more intelligence might be applied in this area. But there's no evidence for that theory. David Davis put in a good showing at `Mistaken Identity', but since then they seem to have been back-pedalling.
And anyway, it's not like the next government isn't going to be Labour anyway. I suppose there's a remote chance of a Lib-Lab pact, but since the Liberal Democrats will no doubt sacrifice anything to extract some form of PR from such an arrangement, I can't see any likelihood that Blunkett will be in any way restrained.
Posted by Backword Dave, Tuesday, 3 August 2004 11:14 (link):
Whatever happened to local democracy? Granted that Chris is pro-cameras, while I'm ambivalent (but then I've been caught and fined), but reviewing every camera by central government seems particularly stupid for lots of reasons. Statistically speaking, there shouldn't all that many accidents on a given road in any year anyway, so a reduction from 1 in the year before cameras were introduced to 0 afterwards could merely be chance. The only way to assess the effectiveness of cameras is by taking total numbers which should be large enough for significant patterns to emerge (or not, of course).
If the Tories think that local police forces are using cameras to raise revenue, they can insist that all monies raised to donated to a central pot to be paid out to councils according to size/population/need -- then the criterion for camera installation might be public safety rather than revenue raising. The Tories could give their local councillors a chance in the next election by letting them promise to review all local cameras, which would seem cost-effective (it's the sort of thing councillors do quite well). The only people who might object would be commuters who live in Finchley and have to pass through Islington on the way to the city, but who ever drove faster than 25mph in central London anyway?
Posted by Chris Lightfoot, Tuesday, 3 August 2004 11:44 (link):
I should probably clarify this. I'm actually fairly ambivalent on speed cameras. Although I've elsewhere said (words to the effect that) the idea of expecting motorists to obey the law is so hilarious that the government should stick cameras everywhere just for humour value, I'm not seriously expecting DTLR to follow a policy simply on the basis that doing so would make me piss myself laughing.
The wider debate on speed cameras is framed in terms of their effect on road safety. There is as yet no evidence that they have any effect on road safety. The government's statistics (saying that they reduce accidents) are rubbish, and the anti-camera mob's statistics (saying that they increase accidents) are even worse. We know (see the Today study from a little while ago) that hidden cameras are effective in reducing the speed of traffic, but it's not certain that that, on its own, has much effect on the accident rate. Above, I propose a random controlled trial as a way to answer these questions, but it would have to be on a fairly large scale and it's not obvious that people would put up with such a thing.
I also feel that the current speed limits are silly. Those on motorways could be higher without any significant effect on safety (modern cars are very safe; note also that our current motorway speed limits are a fuel economy measure from one of the '60s oil crises and nothing to do with safety); those in towns are much too low. Those in built up areas should be 20mph -- less on narrow roads with parked cars -- and perhaps rising to 30mph on main roads. Why do I care? Because I think that motorists are more likely to obey speed limits if they better reflect conditions. The idea that residential streets are for cars and not for people is one of the most pernicious and destructive features of modern life; it's worth making some attempt to fix it.
(I agree that there's an argument for letting local people decide on camera siting, and one of the people on Today this morning was claiming -- anecdotal evidence ahoy! -- that many rural communities are clamouring for speed cameras to reduce the speed of through traffic, and don't want to have to wait until their quota of three serious accidents or whatever is filled before they get any. But I'm a bit uneasy about law enforcement policy being up to local communities generally, and I'm not certain this is the right place to make an exception.)
Posted by john b, Tuesday, 3 August 2004 22:13 (link):
I think you mistyped "much too low" when you meant "much too high" above, which was slightly confusing...
Posted by Chris Lightfoot, Wednesday, 4 August 2004 00:30 (link):
Quite so. Oops. The relevant bit should read, (emphasis mine)
Posted by Sam, Tuesday, 3 August 2004 11:40 (link):
Who is the Tory MP who got elected when he was about 7?
Posted by Chris Lightfoot, Tuesday, 3 August 2004 11:51 (link):
Well spotted ;)
It's a typo in the data for Michael Spicer, it turns out. The script I used to extract years-of-birth from the MPs' biographies on the Conservative Party web site read `born...' in one paragraph, then `... in 1967' (referring to his marriage) in another, and drew the wrong conclusion. Clearly the lesson here is that political parties need to provide this sort of stuff in XML or something. Or that I need to check my data.
There may be a few other such typos, but not too many, I hope. (They won't affect the length-of-service data in the above post, which was compiled independently by Anthony Wells.)
Posted by Jozef, Thursday, 12 August 2004 14:13 (link):
Parliament is like a swimming pool. Most of the noise comes from the shallow end. Seven year olds going on thirty continue their journey of life ... (smile)
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