Britain’s decision to leave the European Union – the “Brexit” – is a seismic development. A stunning rebuke of the global corporate and bureaucratic elite, the vote has already yielded regime change in London – and shaken the EU to its core as other nations mull departures of their own.
Putting politics aside for a moment, though, the “Brexit” offers a fascinating case study for pollsters – nearly all of whom missed the outcome of the election.
Two polls released just ahead of the big vote showed “Remain” prevailing. According to an Ipsos MORI survey released one day before the voting, 54 percent of Brits were supposed to vote “Remain” compared to only 46 percent voting “Leave” – an eight-point margin of victory. Meanwhile a YouGov poll released on the day of the vote had “Remain” prevailing by a 52-48 percent margin – identical to a follow-up Ipsos MORI survey released on the same day.
“The results are close and it’s too early to call it definitively,” YouGov’s pollsters noted. “But these results, along with the recent trends and historical precedent, suggest a Remain victory is the more likely outcome.”
In fact the outcome was so certain the leader of the “Leave” faction – Nigel Farage – actually conceded the outcome on the day of the vote.
“Looks like Remain will edge it,” he said.
When all the votes were counted, though, “Leave” prevailed 52-48 – meaning Ipsos MORI and YouGov’s final polls missed the mark by eight points.
What happened? Well, when survey results fail to project electoral outcomes any number of factors could be involved.