Aggression Frequency vs. Aggression Factor

Virtually all players who play online these days and use poker tracking software have three basic statistics in their heads-up display (HUD):

1. Voluntarily Put Money in the Pot Percentage (VP$IP)
2. Preflop Raise Percentage (PFR)
3. Aggression Factor (AF)

The first two stats — VP$IP and PFR — relate strictly to preflop play, and provide a pretty good picture of how loose or tight a player is, and how aggressively he plays before the flop. Aggression factor, on the other hand, is a measure of how aggressive a player is on all streets (although you also can track a player’s AF for any given street, as well).

It’s important to note that such statistics are not 100 percent definitive by themselves; it’s not always as simple as looking at a stat and having it equate directly to an action. As is typically the case with any type of statistic, these statistics often require context.

Aggression factor is a good example of this. It is calculated as follows:

AF = (times bet + times raised) ÷ times called

When used in the proper context, aggression factor can be a useful statistic for diagnostic purposes in post-game analysis. For example, if you have an AF of 1 on the flop — meaning you call as often as you bet and raise combined — it probably means you are calling too much and not betting or raising enough. But if, instead, you have an AF of 5 — meaning you bet and raise five times more often than you call — it probably means you aren’t calling enough.

However, aggression factor by itself is not always a terribly accurate statistic for evaluating the opposition for in-game purposes (that is, for use in your HUD), because it factors in neither checks nor folds. A player with an AF of 3 on the flop — meaning he bets and raises three times as often as he calls a bet on the flop — could be a very loose, aggressive player who bets and raises at every opportunity, often with nothing. But a player with an AF of 3 also could be an extremely tight player who spends a lot of time checking and folding, taking action only when he has the nuts.

Instead of relying on aggression factor to gauge the opposition, you might turn to aggression frequency (AFq). Aggression frequency is a statistic similar to aggression factor, but it also factors folds into the equation, while expressing aggression as a percentage of actions. Aggression frequency is calculated as follows:

AFq = (times bet + times raised) ÷ (times bet + times raised + times called + times folded)

For example, if a player has an AFq of 75 percent, it means he takes aggressive action 75 percent of the time (or three times out of four opportunities), or three times more often than not. Aggression frequency is more accurate than aggression factor for profiling purposes because it also factors in folds, whereas aggression factor does not (AFq ignores checks because it is not practical to determine whether a player checked out of weakness or in an attempt to check-raise). As a result, aggression frequency does not suffer from the ambiguity of having the same level of aggression being able to simultaneously represent both a maniac and a nit.

Consequently, I believe that aggression frequency is the better statistic to use in the HUD for profiling purposes. Meanwhile, you might use aggression frequency in conjunction with the checking-percentage statistic to put that aggression into greater context. ♠

Jeff Hwang is a semiprofessional player and author of Pot-Limit Omaha Poker: The Big Play Strategy and Advanced Pot-Limit Omaha: Small Ball and Short-Handed Play. He is also a longtime contributor to the Motley Fool. His latest two books — Advanced Pot-Limit Omaha Volume II: LAG Play, and Volume III: The Short-Handed Workbook — were released in October 2010. You can check out his website at jeffhwang.com.