[at-w]

There's interesting data on the accuracy of US presidential markets if you're interested in this kind of thing. It's especially remarkable how accurate they were (both at predicting the outcome and how close the results were) many decades before modern political polling came on the scene.

>As a basic if unsophisticated measure of the accuracy of the betting markets, the favorite almost always won, the only exception being in 1916 when betting initially favored the eventual loser (Hughes) but swung to even odds by the time the polls closed. In the 15 elections between 1884 and 1940, the mid-October betting favorite won 11 times (73 percent) and the underdog won only once (when in 1916 Wilson upset Hughes on the West Coast). In the remaining three contests (1884-92), the odds were essentially even throughout and the races very close.

https://users.wfu.edu/strumpks/papers/BettingPaper_final(JEP...

https://www.sportsoddshistory.com/other/potus-odds/