The latest instalment of our weekly series, in which we use the Centre for Cities’ data tools to crunch some of the numbers on Britain’s cities.
There are many reasons why someone might have voted for Britain to leave the European Union. Belief in national sovereignty; concerns about immigration; straight up racism.
There are reasons to think, though, the one of the big ones – this is going to be controversial, but it does seem to be true – might be lack of education.
[Brief pause, while I delete my email address from the "contact us" page and build a bunker of some sort.]
Okay, that's not entirely fair. For one thing, we're looking at aggregated, city-wide data here. Cities with (spoilers) more educated populations were less likely to vote leave – but that tells us nothing about the individuals within them.
For another – say it with me – correlation is not causation. The fact that more educated cities were full of remain voters might be because of some entirely unrelated factor, to do with culture or economics or something else I haven't even thought of.
Those caveats out of the way, though, the results on this as pretty clear cut. Here's an interactive map showing the proportion of working-age residents in each city that have NVQ4 level qualifications or above (graduates, basically). Darker dots mean higher numbers:
That doesn't immediately look like any obvious pattern. But look at the cities which make the top 10:
That’s two university cities, Oxford and Cambridge; three Scottish ones (Edinburgh, Aberdeen, Glasgow); Bristol, Cardiff, London, and a couple of the capital's plush commuter towns (Reading and Brighton).
Now look at this chart we published on Monday, showing which cities had the highest votes for Remain. The two aren't directly comparable – ours uses local authority boundaries, not (larger) Primary Urban areas, and we covered fewer cities.
This time, the top 10 includes Oxford and Cambridge; three Scottish cities (Edinbrugh, Aberdeen, Glasgow); Bristol, Cardiff, London and Brighton. Nine cities are in the top 10 on both lists.
(The only substitution, incidentally, is that we've lost Reading for Manchester. My guess is that's because the Manchester local authority has a quite different profile to the Manchester PUA, which includes 10 boroughs instead of one. But I'm guessing.)
Here's a scatter graph, plotting graduate population against Remain vote in the 29 cities that are in both data-sets. Once again, it's worth remembering that these are using quite different boundaries, something you'd expect to have an impact on any correlation.
That is a correlation co-efficient of 0.84. Which is really, really high. Even though it's different boundaries, and so yada yada yada.
There could be other factors at work here, and Paul Swinney, the chief economist at the Centre for Cities, has been trying to work out what they might be. (His charts use the "leave", rather than "remain", vote so the correlation runs the other way. Also, where a point is on 0 per cent, that's a lack of data, not a city with no graduates whatsoever or some such.)
Here's Pauls chart plotting graduate populations against the leave vote:
This one is residents without five good GCSEs (the closest we have to a sort of school leaving certificate):
This one is residents in skilled manual occupations:
Lastly, one that's rather less clear, plotting wages against leave vote:
So – income wasn't a huge factor. But education level and type of occupation were pretty clearly factors in how people voted last Thursday.
Or, to put it another way, it seems a lot like less educated people were more likely to vote Leave.
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Jonn Elledge is the editor of CityMetric. He is on Twitter, far too much, as @jonnelledge.