Polymarket is Up to 94% Accurate In Predicting Outcomes: Analysis

Leading prediction market Polymarket is most accurate four hours out from when an event happens, at 94% accuracy, according to Alex McCullough, who put together a Dune dashboard on Polymarket’s performance.

At 12 hours out, this drops to 90%, then drops again to a still impressive 88.5% one day out. One week out, it climbs to 89%, then up to over 90%, one month out.

Speaking on Polymarket’s blog, McCollough explained that Polymarket gets more accurate one month out as there tend to be more extremely unlikely, long-shot markets in which the result is a nearly forgone conclusion. He gives the example of the likelihood of California Governor Gavin Newsom being elected President in the last election cycle.

In a note on his Dune page, McCollough explains that only slightly more than a quarter of markets resolve to the “yes” answer. He explains this as due to the high number of long odds markets.

The numbers are not as accurate in sporting event markets. There are several reasons for this, he explains on Dune.

Markets with long odds of less than or equal to 5% probability “are highly accurate and constitute a significant portion of Polymarket’s total markets, boosting overall accuracy,” McCollough said. “In contrast, such long odds are rarer in head-to-head sports markets, making Polymarket’s accuracy appear lower in this segment.”

Polymarket also tends to overestimate the probability of events happening, but only by a couple of percentage points. McCollough gives a couple of potential reasons for this, starting with acquiescence bias, meaning people who are uncertain tend to answer “yes” more frequently.

Then there’s herd mentality, meaning that when a market trends positively in the direction a bettor wants it to resolve, they tend to pile in.

Finally, there’s low liquidity, which could affect markets’ accuracy, making them lag.