data scientist Alex McCullough's research shows that the prediction market Polymarket has an accuracy rate of 90% when predicting events that occur one month later, and a high accuracy rate of 94% four hours before the event occurs. McCullough analyzed Polymarket's historical data and found that the platform slightly but consistently overestimates the probability of events occurring in most probability ranges after excluding extreme probability values, possibly influenced by herd mentality, low liquidity, and participants' preference for high-risk bets.