The 2016 polling error was modest and in line with historical polling errors, yet large enough to give Trump many paths to victory.

Judged as of November 2016. The claim has three parts: the 2016 polling error was modest; it was in line with historical polling errors; and it was large enough to give Trump many paths to victory. True: post-election analyses (e.g. the AAPOR 2017 evaluation, FiveThirtyEight data) show the national polling error (about 1–2 points) and the average state-level error were within the historical range for presidential elections, and that a uniform error of that size flipped enough states for Trump to win. Mostly true: the national error was historically typical but state-level errors in key Midwestern states were somewhat above average, which the claim plays down. Mixed: the national error was in line with history but state errors were clearly larger than historical norms, so only part of the claim holds. Mostly false: the errors overall were historically large, though correlated errors did open paths for Trump. False: the 2016 polling error was far outside historical norms.

Set before the research began.

1. E1 AN EVALUATION OF 2016 ELECTION POLLS IN THE UNITED STATES AAPOR Ad Hoc Committee on 2016 Election Polling

   “National polls were generally correct and accurate by historical standards.”

2. E2 AN EVALUATION OF 2016 ELECTION POLLS IN THE UNITED STATES AAPOR Ad Hoc Committee on 2016 Election Polling

   “Analysis of 423 state polls completed at least 13 days before the 2016 election, shows an average absolute error of 5.1 percentage points and a signed error of 3.0 percentage points in the direction of over-estimating support for Clinton. In the four prior presidential elections, the average absolute error in state polls ranged from 3.2 to 4.6.”

3. E3 Polling in the age of Trump highlights flawed methods and filtered realities The Conversation · 26 November 2024

   “From 1968 to 2012, the average polling error in the national popular vote was 2 percentage points. That would make 2016 an average year for presidential polling.”

4. E4 How Trump could win the 2020 election through the Electoral College Vox · 29 October 2020

   “Polls underestimated Trump’s margin in most states in 2016, but the misses were bigger than average in or near the Upper Midwest (underestimating Trump by 8 points in Minnesota, a little over 7 points in Wisconsin, a little over 6 points in Ohio and Iowa, nearly 4 points in Michigan, and nearly 3 points in Pennsylvania).”

AAPOR found national polls accurate by historical standards (E1), and The Conversation puts 2016 national error at about the 1968–2012 average of 2 points (E3). State polls, however, had an average absolute error of 5.1 points, above the 3.2–4.6 range of the four prior elections (E2). Misses were larger than average in or near the Upper Midwest (E4). The national part of the claim holds, but AAPOR's figure for state polls completed at least 13 days before the election (5.1 points) is above the 3.2–4.6 range of the four prior elections, which fits the mixed criterion.