Aggression Factor

(AF)
stats

(Bets + Raises) / Calls — how aggressively a player plays.

AF < 1 = passive, 1–3 = balanced, > 3 = aggressive. Postflop AF over multiple streets is more meaningful than a single number.

See also

VPIP
% of hands a player voluntarily enters (excludes blind posts).
Fold-to-CBet
% of times a player folds to a continuation bet.
WTSD
% of pots a player sees showdown after the flop.