Category: Politics

Politics in the UK, with a Liberal Democrat (LibDem) slant

May 06 2010

No sleep ’til Batley!

I’m planning on staying up late tonight, watching the results of the general election come in, this is an occasion for a graph. The chaps at tweetminster have uploaded a list of predicted declaration times here. I’ve rearranged the data a bit to plot it, the height of each bar tells you the number of constituencies declaring during the hour starting at the time indicated at the bottom of the bar. As you can see, things don’t really get going until about 2am. Key times for me are the declaration in my own constituency, City of Chester, at 3am and Dr Evan Harris’ Oxford West and Abingdon at 2:30am. Batley & Spen declares at around 5am hence the title of this blog post.

This has been the most exciting election campaign, and election night, in quite sometime. I spent the 1997 election at a friends house in Darlington, I remember stumbling out into the early morning with “Things can only get better” ringing in my ears. For a few years that seemed to be the case. 1992 was interesting in that we all thought John Major was going to lose, and then he won to the surprise of everyone (including John Major). 2001 and 2005 were rather dull.

As a seasoned Liberal Democrat I’m used to my party getting pretty good percentage poll scores overall and winning pitiably few seats, so to the newcomers out there – welcome to my world! I can only hope that this time things will be different.

Apr 28 2010

Opinion polls and experimental errors

I thought I might make a short post about opinion polls, since there’s a lot of them about at the moment, but also because they provide an opportunity to explain experimental errors – of interest to most scientists.

I can’t claim great expertise in this area, physicists tend not to do a great deal of statistics unless you count statistical mechanics which is a different kettle of fish to opinion polling. Really you need a biologist or a consumer studies person. Physicists are all very familiar with experimental error, in a statistical sense rather than the “oh bollocks I just plugged my 110 volt device into a 240 volt power supply” or “I’ve dropped the delicate critical component of my experiment onto the unyielding floor of my lab” sense. 
There are two sorts of error in the statistical sense: “random error” and “systematic error”. Let’s imagine I’m measuring the height of a group of people, to make my measurement easier I’ve made them all stand in a small trench, whose depth I believe I know. I take measurements of the height of each person as best I can but some of them have poor posture and some of them have bouffant hair so getting a true measure of their height is a bit difficult: if I were to measure the same person ten times I’d come out with ten slightly different answers. This bit is the random error.

To find out everybody’s true height I also need to add the depth of the trench to each measurement, I may have made an error here though – perhaps a boiled sweet was stuck to the end of my ruler when I measured the depth of the trench. In this case my mistake is added to all of my other results and is called a systematic error. 

This leads to a technical usage of the words “precision” and “accuracy”. Reducing random error leads to better precision, reducing systematic error leads to better accuracy.
This relates to opinion polling: I want to know the result of the election in advance, one way to do this would be to get everyone who was going to vote to tell me in advance what their voting intentions. This would be fairly accurate, but utterly impractical. So I must resort to “sampling”: asking a subset of the total voting population how they are going to vote and then by a cunning system of extrapolation working out how everybody’s going to vote. The size of the electorate is about  45million, the size of a typical sampling poll is around 1000. That’s to say one person in a poll represents 45,000 people in a real election.
To get this to work you need to know about the “demographics” of your sample and the group you’re trying to measure. Demographics is stuff like age, sex, occupation, newspaper readership and so forth – all things that might influence the voting intentions of a group. Ideally you want the demographics of your sample to be the same as the demographics of the whole voting population, if they’re not the same you will apply “weightings” to the results of your poll to adjust for the different demographics. You will, of course, try to get the right demographics in the sample, but people may not answer the phone or you might struggle to find the right sort of person in the short time you have available.The problem is you don’t know for certain what demographic variables are important in determining the voting intentions of a person. This is a source of systematic error, and some embarrassment for pollsters. 
Although the voting intentions of the whole population may be very definite (and even that’s not likely to be the case), my sampling of that population is subject to random error. You can improve your random error by increasing the number of people you sample but the statistics are against you because the improvement in error goes as one over the square root of the sample size. That’s to say a sample which is 100 times bigger only gives you 10 times better precision. The systematic error arises from the weightings, problems with systematic errors are difficult to track down in polling as in science.
So after this lengthy preamble I come to the decoration in my post, a graph: This is a representation of a recent opinion poll result shown in the form of probability density distributions, the area under each curve (or part of each curves) indicates the probability that the voting intention lies in that range. The data shown is from the YouGov poll published on 27th April. The full report on the poll is here, you can find the weighting they applied on the back page of the report. The “margin of error” of which you very occasionally hear talk gives you a measure of the width of these distributions (I assumed 3% in this case, since I couldn’t find it in the report), the horizontal location of the middle of each peak tells you the most likely result for that party.

For the Conservatives I have indicated the position of the margin of error, the polling organisation believe that the result lies in the range indicated by the double headed arrow with 95% probability. However there is a 5% chance (1 in 20) that it lies outside this range. This poll shows that the Labour and Liberal Democrat votes are effectively too close to call and the overlap with with the Conservative peak indicates some chance that they do not truly lead the other two parties. And this is without considering any systematic error. For an example of systematic error causing problems for pollsters see these wikipedia article on The Shy Tory Factor.

Actually for these data it isn’t quite as simple as I have presented since a reduction in the percentage polled of one party must appear as an increase in the percentages polled of other parties.

On top of all this the first-past-the-post electoral systems means that the overall result in terms of seats in parliament is not simply related to the percentage of votes cast. 

Apr 27 2010

Occupations of MPs

Ever alert to the possibility of finding some data to play with I was interested in an article in the Times regarding the number of MP’s with scientific backgrounds in parliament. First I found data on occupations in the population as a whole here (Office of National Statistics) and data on MP’s here, published by parliament. I thought it would be interesting to compare the two sets of figures, this turns out to be rather difficult because they define occupations very differently so I had to do a bit of playing about to get them into roughly comparable form.

This is what I came up with in the end:

It’s a “representation factor”, that’s to say I take the fraction of MP’s in parliament having a particular occupation and I divide it by the fraction of that occupation in the general population. If that occupation is over-represented in parliament then the number is bigger than one and if they are under-represented then it’s smaller than one. It would seem barristers, journalists and career politicians are massively over-represented. Lecturers, civil servants and teachers are a little over-represented. Business people are about as expected and doctors are under-represented (along with manual workers and white collar workers).
I think from all of this the figure on doctors is the most surprising. It does make you wonder about how useful the outside interests of MP’s are in guiding their deliberations since most occupations are grossly under-represented. You shouldn’t really expect to see the House of Commons faithfully representing the overall working population, but I expected the balance amongst professionals to be a bit more uniform.
The House of Commons library document on “Social background of MPs” from which I got the MP occupation data is rather interesting, in particular the age profile (table 1) appears to be shifting upwards despite the greater youth of the party leaders. The educational background (table 7) is quite striking too.
One of the glories of the internet is that data monkeys like me can find tasty fruit to pick and consume.

Apr 12 2010

Why I’m voting Liberal Democrat

In a change from usual service I’m writing a political blog post, to cut to the chase: Vote Liberal Democrat! This post tries to explain why.

I’ve been a member of the Liberal Democrats since I was an undergraduate at Bristol University, 20 years ago. As a student I attended a party conference, did a bit of canvassing and I was also a “teller” a couple of times. Since then I’ve been in cover, very deep cover, I pay my monthly membership and a bit extra at election time and that’s pretty much the limit of my activism.

As a casual Liberal Democrat I don’t keep a close eye on party policy, essentially I rely on them being my sort of people and doing the right thing, it’s with some relief I can report that I agree entirely with Nick Clegg in his interview with The Observer this week. The whole interview is well worth a read, but I’ll pick up on one point: there’s a real value in a hung (or balanced) parliament with no party in overall control. Reducing the national debt will be a priority for any incoming government, this is likely to be at least a bit painful and I think it’s very obvious this is better done with a government that holds representatives from more than the 40% or less of the popular vote that a majority government is likely to get.  Many other issues will be with us for years to come: care for the elderly, climate change, pensions, the shape of our democratic systems. The solutions that politicians come up with should be robust, and have cross-party support, on recent evidence they need to work on this cooperative aspect of politics. Across the world and the UK, in devolved government and European elections we use a form of proportional representation, the sky has not fallen in. I’m fed up with the “smack of firm government” that first-past-the-post gives us.

The expenses scandal has had a big impact on politics in the last year, the Liberal Democrats came out well on this with relatively few outrageous claims and a very definite plan on how to address the problem which unfortunately was not picked up by the other parties. MPs had an expenses system which begged to be abused, I’m sure that with the same system at the place I work we would see a similar range of behaviour.

I’ve written in the past about the science policies of the Liberal Democrat, Labour and Conservative parties based around a debate organised by the Campaign for Science and Engineering in the UK. In summary, science has done fairly well by Labour over the last 13 years, with a noticeable wobble at the end over the science advisers, particularly on drugs advice. The Tories seem rather uncommitted to science, and look like they would do no better over science advisers. In the Liberal Democrats we have a champion in the form of Dr Evan Harris, who I really wish was my MP. He has done sterling work on the Science and Technology Select Committee, as well as campaigning on libel reform.

I vote in the City of Chester constituency, pragmatically there is absolutely no point in me turning out to vote. It will have no effect on the outcome, come May 7th not one particle of an MP in parliament after will have my electoral support.

Often party X will tell Liberal Democrats to vote for them to prevent party Y getting in, my response is in the form of an analogy: if I want chocolate cake for pudding the offer of an apple or a plate of cheese and biscuits will not satisfy, and may cause offence and derision. Vote for chocolate cake, vote Liberal Democrat!

Mar 28 2010

Bashing the bishops

I’m sorry, I try really hard to be a quiet little atheist and not cause needless offence, but sometimes the perfect storm hits and I go a bit “Richard Dawkins”.

The spark that lit my ire today was on Radio 4’s Sunday program. It was the juxtaposition of the reports on further problems the Catholic church was having with covering up child abuse by the priesthood with a complaint that Catholic adoption agencies, unlike any other adoption agency, should be allowed to discriminate against gay couples because they didn’t think any gay couple was suitable to look after children.

Can you hear the sound of me bursting a blood vessel here?

This isn’t an isolated incident either, also in the news today: a  letter by six bishops to the Daily Telegraph complaining of the treatment of a nurse who was asked to remove her crucifix necklace, or wear it  inside her clothing. The hospital involved has a policy on uniform which excludes the wearing of necklaces, this seems quite reasonable in my view. I don’t want anyone’s necklace dangling in my wounds, regardless of the form it takes. Now it may be that necklace wound dangling isn’t a problem, and the whole policy is pointless. But that isn’t the argument that the bishops are making, they’re happy with the idea that any random atheist should be prevented from wearing, for example, their bourbon chocolate biscuit necklace but the same rule applied to a Christian is a great offence. It’s a dogmatic position too, wearing the necklace inside her clothing (an entirely acceptable solution I would have thought) is not acceptable to the bishops either.

These aren’t isolated incidents, there are exceptions in law covering the slaughter of animals for both halal and kosher slaughter. So whilst it’s a illegal to slaughter an animal without first rendering it unconscious if you’re a Christian or an atheist, as a Jew or a Muslim it becomes legal. What part does the slaughterer’s religion play in the cruelty or otherwise to the animal? Also in the news recently were the ceremonial daggers worn by Hindu’s. In this instance a child was withdrawn from school for continuing to wear his ceremonial dagger, personally I think banning children from taking knives of any sort into schools is a fairly good idea and once again notice the dogmatism – a compromise solution of a knife welded into it’s scabbard was not acceptable.

We have a wide range of laws which restrict our behaviour for one reason or another, some of those laws are good and, no doubt, some of them are bad. My argument is that no behaviour is unacceptable for one person but acceptable for another simply on the grounds of their religion.

Thank you for hearing my rant!