Study finds no robust cognitive harm from Ramadan fasting in chess
7 reported
A new study analyzing nearly 300,000 tournament chess games found no robust evidence that Ramadan fasting impairs cognitive performance among expert players. The research, conducted by Samuel Buckland and David Smerdon, examined more than 25 million moves made by almost 10,000 players from 178 countries over 10 years. The study used a strong chess engine to objectively evaluate move quality. In the preferred statistical specification, researchers found no impact on overall move quality or shares of optimal moves, with estimates tightly bounded around zero. Muslim players made 0.13 additional percentage points of large errors during Ramadan, but the authors describe this small estimate as fragile across alternative measures and samples. The study notes that more than 2 billion people participate annually in Ramadan fasting, making its potential effects important for workplaces, education, and high-stakes decision-making.
What’s reported
More than 2 billion people participate annually in Ramadan fasting.
The study analyzed nearly 300,000 games and more than 25 million moves by almost 10,000 expert players from 178 countries over 10 years.
Two validation exercises supported the Muslim-status classification, covering almost 11% of the sample.
Survey evidence indicated substantial Ramadan fasting compliance among Muslim chess players.
In the preferred intention-to-treat specification, no impact was found on Muslim players’ overall move quality or shares of optimal and nearly optimal moves.
Muslim players made 0.13 additional percentage points of large errors during Ramadan, but this estimate was fragile across alternative measures, samples, and definitions.
The study concluded there is little robust evidence that Ramadan fasting broadly impairs cognitive performance among expert chess players.
Key figures
Samuel Buckland (researcher)
David Smerdon (researcher)
Sources: marginalrevolution.com
