David Cameron's speech revisited

I started this post as a response to Anonymous in the comments of 'Look who's wearing the Emperor's pants', who asked for an analogy because my statistical analysis is hard to follow. That's fair enough, because it is. In fact, it's so hard to follow that creating the analogy made me realise I'd made a mistake in one of my assumptions about how Cameron's speech is trying to hoodwink with its eastern European figures.

Yes, I did give myself an ironic lolly and call myself 'Lumpy'.

Here's a clearer idea of what's wrong with the figures I looked at in Cameron's speech yesterday. I'll be starting by using barrels and marbles for the easier stuff, and then dropping the analogies for the things that are more dishonest than I'd at first realised.

Net migration
Okay, imagine a barrel. The barrel has 750 marbles in. It springs a leak, and 250 marbles go cascading cross the floor. while this is going on and the leak is plugged, you tip more marbles in to replace the ones spilling out, but you end up pouring in 500 marbles. You've now got a barrel with 1000 marbles in it.

Now, you need to measure how many new marbles had been added to the barrel. You just count how many you tipped in. That would be 500. This would be how we measure total immigration.

You would make a different calculation if you wanted to know how much the number of marbles in the barrel has grown by. That's pretty easy, right? You started with 750 and now you have 1000, so the number of marbles in the barrel has grown by 250. This is the same way we measure net migration.

David Cameron uses the net migration figure in his speech. This is totally fine for what he's doing, and there aren't any problems with it at all.

Foreign-born people added to the job market
We've got another barrel. This one has 750 marbles in too. 650 are blue and 100 are red. It springs a leak, and 500 marbles spill out, 450 of them blue and 50 red. You pour in replacement marbles from a barrel that is made up of a mix of red and blue marbles, but you pour enough to end up with 1000 marbles in the barrel.

You end up pouring in 450 blue marbles and 300 red ones, adding a total of 750 to the barrel. This leaves a total of 650 blue and 350 red in the barrel.

Now you need to know how many marbles are in the barrel that weren't there before. You'd just do the same calculations you did for net and total migration from before. Which one you used would depend on what you were looking for.

The way the government usually does this when they're asked how many people have been added to the job market is by using the net figure. They're basically saying, "When we took over looking after the barrel there were 750 marbles in it and now there are 1000, so we've added 250 to the total number of marbles in the barrel". This is okay as far as it goes. A government can't really take credit for adding people to the job market if they're just taking the place of people who left. But things start to get complicated when you try to split things up, and the net figure stops being very useful.

Let's say someone asks you what the proportion of the marbles you poured into the barrel were red. You poured in 750 marbles, and 300 were red. That means 40% of the new marbles were red. Easy.

This is not how the tabloids, and now David Cameron, would measure it when looking at what you'd done when they took over the barrel. They would say, "250 marbles were added to the barrel by the previous owner. There are 250 red marbles in the barrel that weren't in there before. Therefore all the marbles added to the barrel were red."

That's just not right. More blue marbles were added than red ones, they just all took the place of the marbles that leaked.

Migration from the EU
For this, we're going to have to dispense with the marbles analogy. What Cameron has actually done here is even more dishonest than I imagined, which is why I got confused in the first place. Marbles would only confuse things further. Here goes.

What this part of the speech aims to do is show that immigration from the EU has been both low and high at the same time. He needs to do this to show that being in the EU doesn't have much effect on what can be done to restrict immigration at the same time as telling us immigration from eastern Europe is scary high.

Here's how he does it. First, he's already made sure he's let us know that net migration since 1997 has been about 2.2 million a couple of sections earlier. Now we have that figure in our head. This most likely comes from the Long Term International Migration figures, which you can see here.

Then, he tries to show how teeny-tiny net EU migration has been by restricting himself to one year's worth of figures. So we end up thinking about net EU migration for one year in relation to overall net migration for thirteen years.

If you wanted to give an honest idea of how much being in the EU affects our ability to restrict immigration, you'd show how much EU migration compares to non-EU over the same period. Net migration from the EU between 1997 and 2009 stands at 680,000. That's about a third of the 2.2million total.

This is still low, and would still help with Cameron's point. But 27,000 sounds way lower when you've already heard the 2.2 million figure bandied about.

Now he's got us thinking about how ridiculously low EU migration is, he needs us to think migration from eastern Europe is really high.

He does this by shifting to a total figure since 2004, rather than stay consistent with using net figures. On top of that, the total figure he uses is a nonsense, it's a complete tabloid confection. As I said in 'Look who's wearing the Emperor's pants':
The 'over a million' figure is arrived at using the well trodden technique pioneered by the unparalleled James Slack of counting every application for a Work Permit recorded by the Worker Registration Scheme and ignoring the following things that some people might think was, I don't know, completely fucking essential if you want to work out how many people have come to live and work in the UK: 
a) whether the applications were accepted or rejected
b) how many applications are from people who have applied before, returned to Eastern Europe and want to come back again
c) whether the people who applied actually followed things through and came to the UK
d) how many of these people actually returned home
We've now totally lost contact with reality.

If Cameron had any desire for honesty here, he'd be using net figures from the same source. If he did that, he'd have been talking about net migration from eastern Europe being 304,000. Slightly less than 'over a million', huh? Even if he wanted to cheat and use a total calculation to make it look bigger, we'd be talking about 490,000.

But if he'd been honest, our Prime Minister wouldn't have been able to sound quite so impressive, going from 2.2 million to 27,000 to 'over a million'.  The only honest figure there is the first one.

If even I, who was looking for clues as to how dishonest this speech was managed to underestimate how bad it was, what chance did people not being so careful have?

So, thank you to Anonymous for making me look closer at my working. Without that, I'd have just thought it was a simple matter of switching between net and total calculations when convenient. It was much more than that in the end.


Ceiliog said...

David Cameron - Putting the "rick" & "ant" onto PR.

Anonymous said...

Hang on. How are people supposed to rationalise "over a million" as the Eastern European subset of 27000 anyway? Am I missing something or is he counting on people being lazy and/or dim?

Anonymous said...

Thanks, the analogy really did help :) The revelations though sure are depressing... the abuse of statistics (i expect it from the papers, but from the government!) is almost sinister.

P. Stable said...

Having been away for a while I've only just caught up with another piece of tabloid-inspired dishonesty from the same speech.

During the section on bogus colleges, as an example of "how ridiculous things have got" he points to an Indian organisation that helps arrange student visas and boasts an advert that has "GET A FREE RIDE TO THE UK" plastered across it.

Cameron, and the Mail et al earlier in the year, sought to suggest that this was all about scamming the immigration authorities and claiming benefits illegally. But they had (probably deliberately) failed to twig that it offered a free ride TO the UK, not a free ride IN it.

The company, which provided a perfectly legal service, was simply running an offer in order to drum up trade, with prospective students applying via the company being given a free flight to the UK as a bonus.

It's no different to a million and one similar offers of free flights, holidays and upgrades made by British companies every day. It's like the French president trying to claim that the Sun offering cut-price cross-channel ferry travel is evidence of flaws in the immigration system at Calais.