For those who want the UK to remain a member of the EU, recent polling data may have been keeping them up at night.
The momentum is gathering pace: Of the last eight polls conducted, Leave has won four by a margin of at least three points, while there’s been one tie and Remain has staggered ahead in a few by one or two points.
And the UK also appears to have largely made up its mind; across a variety polls, the number of undecided voters has fallen.
Given how certain Britons now are now speculated to be, a large amount of focus has shifted to turnout, with both campaigns focusing heavily on just getting their sides to actually vote on the day.
But are the polls a good guide to how people will actually vote?
“I doubt very much that a large number of Britons will be changing their minds ahead of the vote,” says professor Matthew Goodwin, a fellow at Britain In a Changing Europe.
“On the question of Europe our society is heavily polarised. Remain and Leave draw their votes from two very different sections of society and among voters who think very differently about the world around them.
“These views are deeply entrenched and so the positions of the two sides are largely priced in. The key question now is which side can do a better job of mobilising and turning out to vote their respective supporters.”
YouGov’s Anthony Wells, who works in the political team, doesn’t agree. “Most people will have just started paying attention, so not everyone has made up their minds.
“We don’t have a great tradition of referendums in this country, and the ones we have suggest a lot of movement over the last few weeks - and more often than not, the movement tends toward status quo.”
Looking at some history, in 2011, the public went to vote in the Alternative Vote referendum. Early polls indicated a large lead for Yes (that is, people wanted the voting system to change from First Past The Post). But in the last months of the campaign voters drifted towards No, and the voting system is still the same today.
Or take the Scottish independent referendum in 2014. There was a solid lead for the No campaign until polls dramatically narrowed in August 2014, before swinging back towards No in September.
In fact, YouGov conducted a poll on the day of the referendum to ask how people would vote, then followed up in the aftermath and found some of those who said they would vote for independence backed the union.
Political commentator Peter Kellner actually assessed that in six of the last seven referenda people have backed the status quo.
The Economist Intelligence Unit’s Aengus Collins explains that the evidence of a late shift due to status quo bias tends to be strong when it comes to referendum questions.
“The argument that people have made their mind up already makes more sense in a general election when, to a greater or lesser extent, people are facing a decision that is broadly the same as one they have made five years previously and perhaps many times before that. They already have a lot of data points to work with.
“With a referendum, on the other hand - particularly one on as broad an issue as membership of the EU - there isn't a comparable decision to refer back to. And so there isn't a line of least resistance that voters can take by relying on the heuristic 'I'll vote the way I usually do'.
“This is one of the issues that makes opinion-polling very difficult in this referendum. It also increases the likelihood that people will second-check their voting intentions in the days, hours or even minutes before voting.”
Wells adds that it’s typical for people to start to focus on risks the closer you get. “People take some sort of step back from that risk, and that can happen very very late in the day.”
That may explain why both campaigns have focussed on risks associated with staying and leaving. On the one side, you have Remain pushing an economic argument, while on the other you’ve got Leave banging the drum on immigration.
But Goodwin doesn’t think that history necessarily applies to the referendum in 16 days’ time. He says that “a more recent review of past voting patterns at referendums has suggested that any swing to the status quo is less pronounced at EU referendums than at referendums on other issues”.
Still, if this referendum is anything like past referendums, Leave would want to have a solid lead going into the past few weeks so they’d still end up ahead after the risk averse ditch their side.