Election 2020: what the data tell us

Polling Methodology and Accuracy Trends

• Pollsters are adjusting for the underestimation of non-college white voters, a demographic that favored Trump in 2016 but was undersampled due to lower poll response rates.
• Undecided voters have dropped to approximately 5% of the electorate, down from over 15% in 2016, increasing confidence in the robustness of Joe Biden's current polling lead.
• Potential polling bias exists if Republicans overestimate their turnout likelihood in response to pandemic safety concerns, despite a higher probability of in-person voting among this group.

Voter Turnout and Swing State Dynamics

• Early voting already accounts for 20% or more of total turnout in several states, significantly exceeding 2016 levels.
• Higher overall turnout historically benefits Democrats, particularly in diverse Sunbelt swing states including Arizona, Texas, Georgia, North Carolina, and Florida.

Modeling Constraints and Variables

• The Economist's forecasting model excludes early voting data due to the lack of reliable, state-level partisan data regarding who casts early ballots.
• Models rely primarily on the state of the economy and presidential approval ratings rather than registration data, which does not always align with actual voting behavior.
• The model historically captures errors from ballot rejection but warns that current spikes in rejections among young, African American, and lower-income voters could cause a 1–2 percentage point drop in projected support for Biden in severe states.
• Ballot rejection concerns stem from structural issues like signature mismatches, address verification difficulties for mobile voters, and slower postal service delivery in lower-income areas, rather than intentional disposal of ballots.

Election Night Projections and Result Uncertainty

• Results for the 2020 election are expected to be clear by 9:00–10:00 p.m. Eastern time, driven by Florida's projection of 90–95% of ballots cast by that hour.
• If Florida votes for Biden early, the model assigns a 95% probability of a Biden victory, as Florida's outcome correlates with trends in midwestern and southwestern states.
• While absentee ballots are expected to count later and may favor Democrats, the probability of the Electoral College outcome flipping after 80% of all ballots are counted is low.

Public Acceptance and Post-Election Stability

• Polls indicate a high likelihood of citizens endorsing violence or unrest if their side loses, particularly if the loss is viewed as undemocratic or if the Electoral College differs from the popular vote.
• Republicans are more likely to question results based on fears of widespread illegal voting, while Democrats may question results if the Electoral College contradicts the popular vote.
• A victory margin of 8–9 points for Biden is projected to reduce the likelihood of the election being called into doubt or triggering significant unrest.