Mon Sep 1st, 2008 at 02:12:22 AM EST
So Eurostat has drafted a news release for its new population statistics, which has been picked up by the Beeb and several blogs, as they show the UK becoming the largest European country in terms of population in 2060.
The UK allegedly is to grow to a population of 77 million by then, and will be bigger than France (72 million in 'Metropolitan' France) and Germany (71 million).
Never mind Turkey...
European countries apparently want to have these numbers, as they have asked Eurostat in a Council resolution to produce them. Still, Eurostat's methodology leaves a lot to be desired.
(crossposted from the DJ Nozem blog)
Front-paged by afew
The data behind the story is basically contained in the report 'statistics in focus 72', where at the bottom you can get the estimates for the numbers that are supposed to drive population growth for the coming 52 years.
There are some big differences here.
Basically, the report works with only one scenario (dumb), which assumes convergence of socio-economic conditions, with 2150 as the convergence point. It is not stated which data was taken as the baseline for this scenario (nor is this stated in either of the notes on the metadata), but it seems to have been the data from the past few years.
A few countries like Italy and Spain have had large inflows of immigrants in the past few years. In Spain's case, this was partly due to the construction boom, partly due to policy. In Italy's case, it was mainly due to immigration from Albania and Romania, who are not going to send such a large number of immigrants to Italy in the medium term.
So we get the odd statistic that Italy will lose 12 million of its current 'natural' population, but will overcome this by adding 12 million net immigrants. Spain will lose 5 million population, but will similarly add 12 million through immigration. Considering the hell that is already being raised in Italy about immigrants, this is an absurd proposition.
By comparison, France is expected to get only 4 million net immigrants.
Long-term population statistic can change rapidly depending upon government policy and natural changes. Last year, the German fertility rate (number of live childs per woman) increased from 1.33 to 1.37, and it might continue to go up this year because of more family-friendly policies. Between 2001 and 2006, the rate increased from 1.63 to 1.84 in the United Kingdom.
Since fertility statistics have a cumulative effect upon total population and even go exponential over a 52 year period, those small differences behind the comma translate into millions by 2060.
Immigration flows can change even more rapidly.
You can see that the predictive power of these statistics is quite low. And it's just the predictions that get reported. The statistics do have a basic if-then quality, but this too is quite low, because they are linear (there's just a line towards a convergence point), and consider only one scenario.
So here's a general rule for longer-term planning: linear, single-scenario models are useless, what is useful for formulating policy are dynamic, multi-scenario models.
(It is quite amazing how many policies are informed by dumb models when you start noticing this. We can do so much better)
Considering that Eurostat only releases these statistics once every 3 or 4 years, there should be enough time and resources for a bit more imagination.