President Trump is trailing in the polls with under two months until the US presidential election. But presidential election polling performed poorly in 2016. So what do the polls really indicate about the state of the race?

New research from the United States Studies Centre (USSC) assesses the 2020 race with the lessons of the past in mind.

Current polling indicates former vice president Joe Biden will win enough swing states to secure a victory, according to The perils of pre-election polling. But given the errors of recent polling in the US — and so much that is unique about the 2020 election — even a large poll lead should not be considered a lock on the election result.

USSC CEO and co-author of the report Professor Simon Jackman says “our goal is to add context to the 2020 polls suggesting Trump is likely to lose. Poll errors in 2016 were large, especially in swing states. Current polls — tempered by the range of errors seen in 2016 — lead us to assess Biden’s chance of winning as no more than about two in three, and Trump’s as no less than one in three.”

The study identifies key areas which proved to be the pitfalls of 2016 polling, including voters deciding late and changes in the American electorate, and factors them into re-interpretation of current polls. The analysis emphasises the outsized role a few key states are again likely to play in the Electoral College and the outcome of the election. 

“Poll averages in North Carolina and Wisconsin— if they are as wrong as they were in 2016 — are currently picking the wrong winner: Biden, instead of Trump," Professor Jackman notes.

The report also considers factors unique to 2020, primarily the impact the COVID-19 pandemic is likely to have on voter turnout and the flow-on debate about mail-in ballots and early voting.

“Amidst a global pandemic, and a fiercely contested election, variability across US jurisdictions in access to the ballot box are likely to be of immense consequence,” Professor Jackman says.

Key points

  • Swing states effectively decide the presidential elections, polling of which systematically underestimated Trump’s strength in 2016
  • Polls currently indicate Biden will win enough swing states to win the election, but with no more than 65.1 per cent probability
  • Forecasts of the November 2020 election outcome ought to be considered especially uncertain, due to the unusual circumstances of the 2020 election
  • Incorporating the distribution of polling errors observed in recent elections improves the accuracy of the 2020 polls.

Report co-author Professor Simon Jackman is available for interviews or briefings. To book an interview or briefing please contact: us-studies@sydney.edu.au.

Media are welcome to use footage from our recent Election Watch webinar 'The perils of pre-election polling' featuring Professor Jackman and Pew Research Center's Dr Courtney Kennedy.

Media enquiries

Taylor Mellor
T 02 9114 2622
taylor.mellor@sydney.edu.au