The Equation What Are the Odds of Cheating?

Extraordinary achievements sometimes spark suspicion, especially when they seem statistically implausible. This happened recently in the world of chess when grand master Hikaru Nakamura won a remarkable 45.5 out of 46 online chess games. Another grand master accused him of cheating, but Shiva Maharaj of CHESS-ED, Chicago Booth’s Nicholas Polson, and George Mason University’s Vadim Sokolov find that Nakamura was likely innocent. Their analysis highlights the prosecutor’s fallacy, which confuses the low chance of seeing a winning streak with evidence of wrongdoing. While the streak’s improbability is striking, it must be weighed against the rarity of cheating among top players. Balancing these factors, the researchers demonstrate that the probability is high that Nakamura played fairly. To learn more, read “Did a US Chess Champion Cheat?”