AFThe AF (Aggression Factor) is a measure of a player's aggression, either in a particular betting round or over all betting rounds. It is calculated as follows:
AF = (num. bets + num. raises) / num. calls
As you can see, this value will be higher the more a player takes the initiative and bets or raises, instead of just calling opposing bets. For example, if a player with a low AF begins to bet, then one can surmise that his hand is truly strong.
VPIP, PFR, WTSD