An election forecaster who previously predicted a landslide victory for Vice President Kamala Harris has switched his prediction to former President Donald Trump.
Thomas Miller, a data scientist who accurately predicted the 2020 presidential election result, previously backed Harris to win in 2024, telling Newsweek in September that the Democrat was on track to win more than 400 votes in the Electoral College, according to his model.
The model, which relies on betting odds as opposed to polling data aggregates, is now saying that Trump is the favorite, with its most recent prediction estimating the Republican could win 345 votes in the Electoral College.
Newsweek has mapped out what a potential 345 Electoral College win could look like for the former president. In this scenario he sweeps the South and Midwest, winning all the states where Harris has only a single-digit lead, per FiveThirtyEight’s forecast.
The model first began predicting a narrow Trump victory on October 7, when betting odds began swinging towards the former president.
Miller’s model prioritizes betting odds over polling data and also uses historical trends from previous elections to balance the data with what he calls “fundamentals,” something that most other models do as well.
For the 2024 election, Miller is using the betting site PredictIt to fuel his model, which was the same data that his successful 2020 prediction was based on.
However, the data and the fundamentals are predicting different results. Miller wrote on his website on October 20 that “technical and fundamental analyses are not in alignment,” as the historical trends indicate a Democratic victory, in conflict with the betting odds saying that Trump will win.
This matches what fellow election forecaster Allan Lichtman has also said about the election. In contrast to other forecasters, Lichtman’s “Keys to the White House” model relies almost exclusively on long term historical trends, and has continually predicted a Harris victory.
While polling still indicates that the race is tight, betting odds have continued to favor Trump, with Polymarket odds showing Trump leading Harris nationally with a 60.3 percent chance of winning, compared to Harris’ 39.7 percent.
While betting odds have consistently predicted the right winner of the presidential election historically, they are not based on the same representational statistics as polling and are therefore more prone to biases.
Donald Trump looks on during a roundtable with faith leaders at Christ Chapel on October 23, 2024 in Zebulon, Georgia. The former president is strongly favored in betting markets this election.
Getty Images
Miller told Newsweek that he corrects for potential biases in his model, which are currently favoring Trump.
“Prediction markets have a Republican bias,” Miller said. “We assessed the degree of Republican bias in 2020, and we currently correct for that degree of bias. What is uncertain, however, is the level of Republican bias in prediction markets in 2024. We are conducting studies across prediction markets that we hope will shed light on the degree of bias in 2024.
“The 2024 race for the presidency has gone from toss-up to Republican landslide, to toss-up, to a possible Democratic landslide, to toss-up, and now to a possible Republican landslide. Could prediction markets and associated election forecasts turn again with less than two weeks before the close of voting on November 5? Yes. We expect to see increased trading and high volatility in the final week of the race.”
In the 11 presidential elections since 1980, the only race where the winning candidate had worse odds than the losing candidate was in 2016, where both the betting markets and conventional polling failed to predict a Trump win.
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