the data diary

The final pre-election forecast gives Kamala Harris a 93% chance of beating Donald Trump in New Hampshire.

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

The Dartmouth Poll

3 November

Likely voters

Online Panel

560

64.8%

35.2%

D +29.6%

University of New Hampshire Survey Center

2 November

Likely voters

Probability Panel

2,729

52.6%

47.4%

D +5.2%

Saint Anselm College Survey Center

29 October

Likely voters

Text-to-Web

2,707

52.6%

47.4%

D +5.1%

Praecones Analytica

26 October

Registered voters

Online Panel

622

49.8%

50.2%

R +0.3%

YouGov

25 October

Likely voters

Online Panel

364

53.6%

46.4%

D +7.1%

Emerson College

23 October

Likely voters

Online Panel/Text-to-Web

898

51.9%

48.1%

D +3.8%

University of Massachusetts Lowell Center for Public Opinion

23 October

Likely voters

Online Panel

558

53.8%

46.2%

D +7.5%

The Dartmouth Poll

18 October

Registered voters

Mail-to-Web

2,127

60.8%

39.2%

D +21.6%

University of Massachusetts Lowell Center for Public Opinion

10 October

Likely voters

Online Panel

546

54.9%

45.1%

D +9.9%

Saint Anselm College Survey Center

2 October

Likely voters

Online Panel

1,999

53.7%

46.3%

D +7.4%

1–10 of 18 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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