Research Summary

Skill vs. Luck in Poker: Evidence from the World Series of Poker

Citation

Levitt, S. D., & Miles, T. J. (2011). The Role of Skill Versus Luck in Poker: Evidence from the World Series of Poker. NBER Working Paper No. 17023. Later published in the Journal of Sports Economics (2014).

Study Overview

Economists Steven Levitt and Thomas Miles looked at whether poker results are dominated by chance, or whether players with a track record of past success actually perform better than average across a large, real-money sample. The debate matters beyond academic curiosity — in the United States, whether poker counts legally as a game of skill or a game of chance affects how it can be regulated.

Methodology Summary

The researchers identified a group of "skilled" players ahead of the 2010 World Series of Poker, based on those players' documented results in major tournaments over the prior three years. They then compared this group's financial results across a large number of 2010 WSOP no-limit hold'em events against the results of all other entrants, who were treated as a comparison group.

Key Findings

• The pre-identified skilled group achieved better average financial results across the sampled events than the rest of the field.
• The gap held up as statistically meaningful given the size of the sample, even though poker tournaments are individually high-variance events.
• The results were consistent with earlier, smaller studies (such as Cabot & Hannum's simulations and DeDonno & Detterman's instructional experiments) that found skilled or instructed players outperforming unskilled ones over enough hands.

Limitations

• The data covers one series, in one year, in tournament formats — it does not directly test cash games, online play, or other tournament structures.
• Defining "skill" using players' past tournament success carries some circularity: it assumes past results are themselves a skill signal rather than pure luck, which is close to the very question being tested.
• The study measures group-level outperformance, not the size of any individual player's edge, and it does not isolate which specific decisions (starting hands, bet sizing, bluff frequency) drove the difference.
• A single tournament series is still a relatively short sample by the standards of poker's known variance; the researchers argued their sample was large enough to detect a real effect, but it remains far smaller than the number of hands needed to fully separate skill from short-run luck at the individual level.

Practical Meaning

This study is evidence that skill plays a measurable, non-trivial role in poker results over a reasonably large sample — it is not proof that any individual session's outcome reflects skill rather than variance. The honest takeaway for a player: expect meaningful short-term swings regardless of how well you play, and judge your own decisions over a large enough sample of hands rather than any single result. See our note on this in the Texas Hold'em guide.

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