The tight US election

There are two reasons why the 2020 US presidential election is taking more time than usual to resolve. One is the pandemic, which led to so many mail-in votes, and thus prolonged the vote-counting process, with the mail-ins—predominantly pro-Biden—counted after the votes cast in person on election day. This is an exceptional problem, which hopefully will no longer exist in 2024.

The second problem is the electoral college system in itself, which requires obtaining a political consensus on 50 voting contests—plus 1 for the District of Columbia—rather than only one, or even a majority, of them. In 2020, with 45 of the statewide results already settled as of now, I guess that 90 percent of the pre-election survey forecasts were correct.

The present uncertainty is due to a handful of so-called “battleground states” where the voting percentage margins between candidates are so tiny that they cannot be predicted by conventional sample surveys. A sampling error margin of plus/minus 1.0 percent, i.e., 1/100, requires a sample of 100 x 100 = 10,000 respondents. For accuracy within 0.5 percent = 1/200, one needs a sample of 200 x 200 = 40,000. Accuracy within 0.1 percent = 1/1,000 requires a sample of 1,000 x 1,000 = 1 million.

As I write this on Nov. 6, 10:30 a.m., CNN’s margins in the last five battleground states are: Arizona for Biden by 1.6 percent, North Carolina for Trump by 1.4 percent, Nevada for Biden by 0.9 percent, Pennsylvania for Trump by 0.7 percent, and Georgia for Trump by 0.1 percent. These margins are simply too small to be called by normal opinion polls.

On Nov. 4 (US time), the American polling aggregator Nate Silver (fivethirtyeight.com) judged Arizona as “likely Biden,” North Carolina as “likely Trump,” Nevada as “likely Biden,” Pennsylvania as “leaning Biden,” and Georgia as “leaning Biden.”

The view of a non-American polling expert: This week, Canadian professor Claire Durand, past president of the World Association for Public Opinion Research, blogged, “I think Biden will win” (ahlessondages.blogspot.com, 11/2/20): “Hi. I rarely commit myself to predict election results. This time, I am quite confident. And I know I will feel very bad on the 4th—or when the final results are known—if I am wrong. Of course, I examined only the national polls but if Biden ends up with less electoral votes and a larger proportion of the popular vote than Trump, it would mean that the system really needs to be changed.”

She thinks that the 2016 polls were within the margin for error. The flaw of lack of weighting by education in the state polls has been corrected in 2020. Another explanation for 2016 was an unexpectedly low turnout of Democratic supporters; but this is not happening in 2020. She says that a last-minute change in voting intention is rare. It was not the cause of the 2015 poll failure in the United Kingdom, as studied by the British Polling Council. The one case of change in voting intention that she knows was in the Quebec 2018 election.

Her conclusion: “For Donald Trump to win, it would be necessary that more than 50 different pollsters with different methodologies be wrong. This is highly unlikely. Electoral polls are often the best polls that you can get because pollsters know that their estimates will be compared with the final results… They are therefore very careful and they try to improve their methods all the time… Even when we ‘load’ the estimates in favor of Trump to simulate a ‘shy Trump’ effect, we are still led to conclude that Biden is sufficiently ahead to win.”

Her final blog of Nov. 5: “Two days after: did all the polls miss their target?” noted newest polls with a bit more support for Trump. “Therefore I tweeted on Tuesday that I still thought Biden would win but that the results would likely be closer than expected… Please note that the proportion of votes for Biden is likely to increase with the counting of the votes and, therefore, the performance of the pollsters will eventually appear better than right now.” (Italics hers. Her average of the final polls’ call of the national vote is 51.3 percent Biden and 48.7 percent Trump.)

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