Can We Really Know Who Will Win the US Presidential Election?
Want to know who is in the lead to win the US presidential election? From the myriad polls out there come myriad answers. Every day a new poll with fresh data is released, calling into question what we should believe. Should we trust the IBD/TIPP Tracking Poll, “the most accurate presidential poll in America”? The USC Dornsife/L.A. Times presidential poll, “a poll unlike any other”? Or Scholastic’s national student poll, which has accurately predicted the winner of every election since 1960?
Recent election results have increased the scepticism around polls. Closer to home, the Brexit referendum shocked Remain voters after average poll numbers leant firmly in favour of the status quo. Just before the referendum, Remain was in a two-point poll lead. “It’s harder and harder to find people willing to pay for any polls, given their poor performance this year and last year. They’re heavily discredited in the UK,” says Stephen Fisher, a political sociologist at the University of Oxford.
From a technological standpoint, part of the problem of accurate poll data in the US is the switch from landlines to mobile phones. Less than a decade ago, polling organisations could ring people directly and find out their opinion. In 2008, more than eight in every ten US households had landlines; by 2015, that number had dropped to five and it continues to decline. With people less trusting of unknown mobile numbers, the pollsters are finding alternative ways of reaching people, using statistical tools to correct for biases and turning to online surveys. Polling aggregates such as FiveThirtyEight, RealClearPolitics and Huffington Post combine and average the results to develop more nuanced forecasts.
Another difficulty for pollsters is predicting who will actually vote. This year will be particularly difficult, since both Trump and Clinton have historically low approval ratings. The majority of America dislikes both candidates. Indeed, there are many who are in support of Trump but ashamed to admit so – what is known as the Bradley effect. This term was coined after the African-American Los Angeles Mayor Tom Bradley lost the 1982 California governor’s race despite being ahead in voter polls going into the elections. The polls were skewed by the phenomenon of social desirability bias, the tendency of survey respondents to answer questions in a manner that is viewed favourably by others.
The limitations of US polls means that they will never be wholly representative of the nation’s opinion. Indeed, a lot of polls are conducted state by state, with many of those being historically Red or Blue. As Tim Furdui, Senior Research Analyst at Atomik Research says, “polls give the right indication but not an accurate margin.” Pollsters are unable to control the sample and there is only one question to play with. Without being able to select a sample that mirrors the demographic of the country, it is impossible to get an accurate balance of opinion from those that may turn out to vote on the day.
This inability to be a truly nationally representative poll explains why many got the Brexit result wrong. It seems that they under-estimated the age-skew in turnout in the same way as the 2015 general election. Politically engaged people were the majority of those polled, and therefore the pollsters’ models were built on the expectation that more of them would vote than they actually did.
However, despite their faults, Tim believes the US polls “have got it right about who’s in the lead and who’s behind.” They’re not meant to be an exact measurement, but instead indicative of the final result.
Real Clear Politics’ poll tracker reveals just how close the race has been. As of today, 25th October, it reports that Clinton has a 5.5 lead. With only a couple of weeks to go until the election, the polls are as accurate as they’ll ever hope to be. The ABC News tracking poll shows Clinton with a much greater advantage: 50% support to Trump’s 38%, a 12 point lead for Democrats. After a series of allegations of past sexual misconduct, the poll finds that some women who would have initially given Trump the benefit of the doubt have since changed their minds. As these two polls show, each one varies in numbers, but the general consensus is that Hillary is more likely to win. It will be interesting to contrast the final results with the polls on November 8th to see just how close they actually were to the outcome.
By Bella Foxwell