No, More People Under 25 Voting Won't Swing The Election Result

TL;DR: You'd need more young people than are actually alive right now to vote in order to force a Labour win.

Last week this tweet went viral.

Alan Firth🇪🇺 @diponte

Simply put, if the vote of 18-24 year olds goes up by 30% compared to last GE, Tories will lose on 8 June https://t.co/87yshswG2z

Thu May 04 17:32:59 UTC+0000 2017

Which led to this headline on The Independent's indy100 site, which repeated the central claim as fact – and quickly became the most viral election story of the whole week.

Indy100

And it's not the only one! Many of the most widely shared election stories of the past week have been about the same idea – that an increase in the number of people between 18 and 24 voting could be enough to swing the election. "It's official: The more young people that vote the more likely the Tories are to LOSE", wrote The London Economic blog, while The Canary had "Students just blew the general election wide open with one hell of a shock for Theresa May".

Because we had nothing better to do, we decided to see if it was actually true. How many more 18- to 24-year-olds would need to vote to swing the election? Let's DO SOME MATHS!

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Let's start with some basic numbers.

To keep this simple, we'll use the results from the 2015 election as our guide. (That's actually a bit generous to Labour's chances, as the Conservatives are currently polling much better than they did in 2015, but let's run with it.) How different would that election have looked if 18–24 turnout had been higher?

Overall, the Conservatives got a total of 11.3 million votes to Labour's 9.3 million – a deficit for Labour of slightly under 2 million votes. Now obviously, UK elections aren't decided by who gets most votes nationally. But it's a good place to start.

So, how many people under 25 didn't vote?

In mid-2015, when the last election was held, there were 5,878,472 people aged 18 to 24 in the UK, according to estimates from the Office for National Statistics. Let's remove Northern Ireland from that (where Labour don't have candidates, so you can't vote for them). That gives us slightly over 5.7 million potential voters aged under 25.

Polling firm Ipsos estimated in its large post-2015 election study that the turnout rate of people aged 18–24 was 43% in 2015. This means that roughly 2.45 million people of that age voted, while 3.25 million didn't. That's a lot of non-voters.

It's also the lowest turnout of any age group, by quite a long way.

Old people are super into voting!

Lisafx / Getty Images

But those who did vote in 2015 went strongly for Labour.

Twitter: @russellhowhard

This bit is undeniably true: The more young people vote, the better it's likely to be for Labour. Ipsos estimated that people under 25 voted for Labour over the Conservatives by 43% to 27%, with the remaining 30% voting for other parties. (That's roughly in line with what other surveys have suggested.)

So what level of extra turnout would be needed for young people to have handed the election to Labour? Well, the original tweet said a 30% increase, so let's chuck that into our big nerdy spreadsheet and see how it goes.

A 30% increase would mean a new turnout of around 56% – which would have meant an extra 737,000 young people voting. Or perhaps they wanted us to just add 30 to 43? It's unclear. If so, 73% would have meant 1.7 million more votes.

You've probably spotted that either way, neither of those numbers is big enough to overturn the Tory lead in the popular vote, even if every single one of them voted Labour.

And of course, they wouldn't all vote Labour.

Danny Lawson / PA Images

Let's assume for now that the young non-voters split the same way as their voting counterparts – 43% for Labour and 27% for the Conservatives. At 56% turnout, that gives Labour an extra 317,698 more votes nationally, which is quite good!

But (this is the crucial bit) it also gives the Tories an extra 198,857 votes at the same time. Every bit of extra turnout adds votes to all parties... meaning the net gains for any one party are much less. In total, 56% turnout would mean that Labour's national vote deficit is reduced to, um, a mere 1.87 million.

Even at 73% turnout, the 1.7 million new voters only give Labour 274,049 extra votes more than the Tories get. That's still nowhere near enough to win – it would leave them 1.7 million votes behind.

In fact, if young non-voters split the same way as those who did vote (which is normally a fairly accurate assumption), even if every single person aged 18 to 24 voted, it would only net Labour 520,693 votes more than the Conservatives would also gain. That's not to be sniffed at, but it still leaves the party almost 1.5 million votes short.

In fact, to overturn the Tory lead in 2015, you'd have needed a turnout among under-25s of, er...261%.

BuzzFeed News

That's right, you'd need two and half times as many young people as actually exist in the country in order for them to change the result.

Which, just to clarify, is not a thing that is possible. UNLESS JEREMY CORBYN IS SECRETLY CLONING YOUNG PEOPLE IN HIS UNDERGOUND LAIR.

Danny Lawson / PA Images

Okay, you're thinking, but what if those non-voters don't split the same way as voters did? What if they're much more likely to prefer Labour?

A survey for the Higher Education Policy Institute showed students backing Labour by 55% to just 18% for the Tories, with 93% of them registered to vote – both big increases on previous elections. That's the basis for quite a lot of the stories about how students could have a big shock in store for Theresa May.

Okay, setting aside the point that undergraduate students aren't necessarily representative of all young people, let's chuck those numbers in and see what pops out. If 55% of young people voted Labour, with 18% going to the Conservatives, and turnout was an unprecedented-in-literally-any-general-election-ever 93%, Labour...would still come up 931,000 votes short.

The better news for Labour is that on these figures, you'd only need 138% of all the young people in the country to vote in order to win the popular vote.

Or to put it another way, even at that wildly unrealistic 93% turnout, under-25s would need to split for Labour over the Tories by 85% to 15% for Labour to change the result. Whichever way you cut it, bluntly: It's not happening.

And that's not the only problem.

Isabel Infantes / EMPICS Entertainment / BuzzFeed after webcomicname.com

The extra problem is that young people aren't evenly spread around the country. They're significantly more likely to live in urban areas than older people are. And seats in urban areas – particularly in large cities – are more likely to already be held by Labour.

As we said right at the start, British elections aren't decided by the national popular vote. So it's absolutely possible for Labour to win the most seats while getting fewer votes nationally, if their voters are more efficiently distributed around the country. (They've actually done that before, narrowly, in the elections of 1929 and February 1974.) But the trouble is that making gains among a segment of the population who are more likely to live in seats that you already hold is kinda the opposite of efficient distribution.

So...young people just shouldn't bother voting? That's what you're saying, right? Why do you hate young people?

Ljupco / Getty Images / BuzzFeed

Whoa there! We did not say that, because we are not monsters who want to crush everybody's dreams. First up, voting is good. Secondly, the fact that young people don't vote anywhere near as much as old people do is why politicians from all parties pander to old people's every whim while basically ignoring the young, and that probably won't change much until young people vote more – regardless of which party they back.

And thirdly, the fact that young people are more likely to live in urban areas (and particularly to cluster around, say, universities) works both ways. It means it's a bit harder for them to change the result of the election on a national level – but it means that they can be very influential in a smaller number of seats.

As this analysis by Novara Media shows, there are quite a few seats where the number of people aged 18 to 24 is bigger than the margin of victory in 2015. (Novara's list is targeted at beating the Conservatives, as they're a left-wing outlet who want to ruin Theresa May's day, but the same principle applies whoever you want to vote for.)

TL;DR: Young people's votes can be pretty important. But if you were hoping that more young people voting could swing the election all by itself, then sorry: There just aren't enough of them.