Table 2. Descriptive statistics for the whole sample. PI: Player of Interest (i.e., player first deviating from a theoretical opening).

Variable		Mean	SE
Elo rating	White	2112.81	.64
	Black	2109.79	.64
Knowledge		16.76	.02
Length		78.73	.12
Result		.537	.0015
PI Elo	Elo	2103.20	.65
PI color	White	49.33%	n/a
PI color	Black	50.66%	n/a
PI relative skill	Weakest	53.36%	n/a
	Best	46.64%	n/a