Votes at 16 are unlikely to change the EU referendum outcome, but could have a positive impact in the long run

The House of Lords has amended the EU Referendum Bill to allow 16- and 17-year-olds to vote in the forthcoming EU referendum. The issue will now return to the Commons, but what difference would such an extension to the franchise make? Alan Renwick and Barney McCay examine the evidence.


On Wednesday the House of Lords voted by 293 to 211 to allow 16- and 17-year-olds to vote in the forthcoming EU referendum, meaning that the issue will return to the Commons. The Electoral Commission has said that if 16- to 18-year-olds are given the vote the referendum could be delayed by as much as 12 months. But how might it affect the referendum’s outcome? We cannot know for sure but by piecing together evidence from various sources we can develop some ballpark estimates.

How many extra electors?

The first question is how many extra eligible voters there would be if 16- and 17-year-olds entered the electorate.  In 2014, there were 1,534,192 16- and 17-year-olds in the UK, while the number aged 18 or over was 50,909,098, putting 16- and 17-year-olds at 2.9 per cent of the 16+ population.  The ONS estimates that this percentage will fall to 2.8 per cent by 2016.

Would they turn out?

A second question is whether these 16- and 17-year-olds would actually vote.  Would they join the electoral register?  And would those registered turn out on polling day?

Last year’s Scottish referendum – where votes at 16 were granted for the first time in the UK – gives some hints on registration.  109,533 16- and 17-year-olds registered. A House of Commons research paper, using ONS population figures, says that this constituted 89 per cent of those eligible. By contrast, many media outlets claimed that 97 per cent of the total electorate registered, suggesting higher registration for the general population than for 16- and 17-year-olds. But we must be cautious. The Electoral Commission rejects such calculations, saying they use unverifiable estimates of the number of eligible voters in the population.

Survey data allow us to go further regarding turnout. ICM interviewed 1,852 people after the Scottish referendum, of whom 112 were 16- and 17-year-olds.  This is a small sample, but it provides an indication of how turnout varied across age groups. The findings are summarised here:

Age bracket 16–17 18–24 25–34 Total electorate
Turnout 75% 54% 72% 84.5%

On the one hand, turnout among 16- and 17-year-olds was about 10 percentage points below overall turnout. On the other hand, 16- and 17-year-olds were more likely to vote than those aged 18 to 34

The same trend is evident elsewhere too. In Austria – the only European state with votes at 16 for national elections – this age bracket votes less than the entire population but more than the subsequent bracket. Eva Zeglovits and Julian Aichholzer demonstrate this through analysis of two local elections, in 2010 and 2012: on the one hand, turnout among 16- and 17-year-olds was about ten percentage points below overall turnout. On the other hand, ICM’s results suggest that 16- and 17-year-olds were considerably more likely to vote than those aged 18 to 34.

Age bracket 16–17 18–20 Total electorate
Turnout: Vienna (2010) 64.2% 56.3% 67.6%
Turnout: Krems (2012) 56.3% 46.3% 62.6%

The same trend is also evident from trials in Norway. In its 2011 local elections, the voting age was lowered to 16 in 21 municipalities. As Jo Saglie has pointed out on Democratic Audit, 16- and 17-year-olds voted more than 18- to 21-year-olds but less than the total electorate:

Age bracket 16- and 17-year olds 18- to 21-year-olds Total electorate
Turnout 58% 46% 63%

Enfranchising 16- and 17-year-olds might therefore reduce overall turnout at first.  On the other hand, Mark Franklin has shown that whether whether a person votes the first time she or he is eligible to vote has a considerable effect on her or his likelihood of voting thereafter.  If enfranchising 16-year-olds increases the proportion of voters who do vote first time, turnout could therefore be expected to rise in the long run.

Would they understand the issues?

In addition to decreased turnout, many opponents of lowering the voting age say 16- and 17-year-olds lack sufficient maturityClayton and Chan, for example, assess 16- and 17-year-olds’ ‘interest in politics’, ‘party identification’, and ‘political knowledge’ to argue that this age group cannot make sufficiently informed decisions at the ballot box.

But evidence from Austria suggests that the quality of young people’s vote is equal to other age groups’ and that the very process of enfranchisement increases political knowledge among 16- and 17-year-olds. One report finds that under-18s’ voting intentions are often more congruent with party positions than older voters’, illustrating their ability to articulate their preferences through the electoral system.

In any case, measures can be taken to increase the quality of younger votes. Austria made a concerted effort to increase registration and raise awareness about elections after introducing votes at 16 in 2007, launching the ‘Demokratielnitiative’ campaign and increasing citizenship education in schools. Zeglovits shows that the number of 16- and 17-year-olds describing themselves as ‘very interested’ in politics doubled thereafter.

Similarly, in Scotland last year Electoral Registration Officers visited schools to register eligible young people, the Electoral Commission ran an advertising campaign targeting 15- to 17-year-olds, and local councils carried out public awareness activities. Education Scotland offered guidance on how educational establishments could increase political literacy. These measures seem to have succeeded. The University of Edinburgh found young people who had discussed the referendum in school exhibited more political confidence and understanding than those who had not. Advertising initiatives also seem to have worked: the proportion of 16- and 17-year-olds who felt that they had sufficient information about how to cast their vote rose from 46 to 74 per cent after they were rolled out.

How would they vote?

Many studies reveal an age-based split in EU voting intentions: younger people are more likely to vote to stay in, older people to leave. An ICM poll suggests that 53 per cent of 18–34-year-olds want to stay, 28 per cent to leave, while 39 per cent of those aged 55 or over want to stay and 46 per cent to leave. ComRes finds 72 per cent of 18–34-year-olds want to stay compared to 46 per cent of those aged 55+.

Opinion polls focus overwhelmingly on the views of those aged 18 and over. The British Election Study did, however, include some under-18s in its panel survey conducted in May. The sample of under-18s is small (280 individuals). But the data suggest that 16- and 17-year-olds fit the trend of younger people preferring to stay.

Alan Barney chart EU ref VI by age

Source: British Election Study, Panel study data 2015


Comprising a small percentage of the total electorate and being somewhat heterogeneous in their views 16- and 17-year-olds, if enfranchised, could swing the referendum result only if the vote is very tight.

However, enfranchising 16- and 17-year-olds in the EU referendum may well set a precedent for future elections, as it did in the Scottish referendum.  If that happened, then, over time, the change might have deeper effects.

Note: This post was originally published on The UK in a Changing Europe and the Constitution Unit blog is re-posted with permission. It gives the views of the author, and not the position of EUROPP – European Politics and Policy, nor of the London School of Economics.

About the authors

Dr Alan Renwick is the Deputy Director of The Constitution Unit.

Barney McCay is a Research Volunteer at The Constitution Unit.

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