the data diary

The final pre-election forecast gives Donald Trump a >99% chance of beating Kamala Harris in Nebraska.

Presidential probabilities

Each day, the model simulates thousands of plausible election results, from landslide victories to tightly contested races. Each candidate’s probability of winning is the proportion of simulations that they’ve won.

Forecasted election-day voteshare

The model first constructs a polling average, pooling data across similar states when polls are sparse. It then projects forward to election day, initially relying on non-polling indicators like economic growth and partisanship, but aligning more closely with the polling average as election day approaches.

pollster

date

population

mode

sample size

harris

trump

margin

Change Research

31 October

Likely voters

Text-to-Web/Online Ad

576

40.6%

59.4%

R +18.8%

YouGov

28 October

Likely voters

Online Panel/Text-to-Web

1,145

42.1%

57.9%

R +15.8%

The New York Times/Siena College

26 October

Likely voters

Live Phone

1,135

42.1%

57.9%

R +15.8%

Change Research

21 October

Likely voters

Text-to-Web/Online Ad

782

42.7%

57.3%

R +14.6%

Change Research

8 October

Likely voters

Text-to-Web/Online Ad

859

39.6%

60.4%

R +20.8%

Torchlight Strategies

8 October

Likely voters

Live Phone/Text-to-Web

564

39.4%

60.6%

R +21.3%

Impact Research

3 October

Likely voters

Unknown

576

39.6%

60.4%

R +20.8%

The Bullfinch Group

1 October

Likely voters

Online Panel

380

44.2%

55.8%

R +11.6%

SurveyUSA

23 September

Likely voters

IVR/Online Panel/Text-to-Web

535

41.7%

58.3%

R +16.6%

Global Strategy Group

29 August

Likely voters

Live Phone/Text-to-Web

546

40.7%

59.3%

R +18.7%

1–10 of 11 rows

State similarities

The model uses state characteristics, like demographic composition, population density, and education, to estimate how similar states are to one another. Similar states are more likely to share polling biases and see similar shifts in polling trendlines.

Sources: Ballotpedia; Cook Political Report; The Economist; Federal Reserve Bank of St. Louis; FiveThirtyEight; Urban Stats; 270towin.com

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