HUD Aggression Stats - How they are calculated & how to use them!

The aggression statistic(s) is part of the traditional “holy trinity” of stats (VPIP/PFR/AF), and it is certainly the most useful “general” postflop statistic that becomes meaningful after just 200-300 hands.

However, through speaking to many of my coaching clients, I am acutely aware of 2 problems relating to these statistics:

1.       People misunderstand the statistics  

2.       People ignore the statistics

If you might fall into the first category, you will glad you invested the next 5 mins of your life reading the rest of this article!

If you just plain ignore the stats, then read on… I am sure this will convince you that this traditional, core statistic, whilst it is nowhere near as important as VPIP/PFR, should at least have demi-god status.

The Story So Far…

The way I see it, part of the problem is that there is an alarming amount of inaccurate information about these statistics online in forums and in articles.

In addition, there were initially some programming errors with these statistics in HM2, which certainly didn’t help the situation. Note that the different tracking software offer different aggression statistics.

How The Stats Are Calculated

Let me define the 3 aggression statistics and give you some guidance: 


1: Aggression Factor (AF)

 = Total Bets + Total Raises / Total Calls


2: Aggression Percentage (Agg%)

= (Total Bets + Total Raises) / (Total Bets + Total Raises + Total Calls + Total Checks) *100


3: Aggression Frequency

= (Total Bets + Total Raises) / (Total Bets + Total Raises + Total Calls + Total Folds) *100


In all cases, we are examining the total number of postflop actions (this has nothing to do with preflop!) and calculating a ratio or percentage of “aggressive” to “passive” actions. So far so good.

Now The Big Question, So Which One Is Best To Use?

Actually, I believe all 3 of these statistics provide great information once you have 200+ hands (more if you play formats with few postflop hands e.g. hyper turbo tournaments). Let’s look at all 3:

1: Aggression Factor (AF)

Aggression Factor (AF) only takes “calls” as the passive denominator. It does not take into account checks and folds, therefore an opponent who checks and folds frequently could be extremely passive, but still have a high aggression factor. What it really does is measure “how much this player likes to call”. Let’s take a look at a few examples:

Player A: VPIP 75 PFR 9 AF 0.5

This is a player who plays passively both preflop and postflop, preferring to call and reluctant to throw large numbers of chips into the pot of his own free will. That means when this player does bet or raise, you ought to believe he has hit something. A bet or a raise from this player is a huge alarm bell that you may not pick up on if you are not paying attention to his AF.

To exploit this player, you make large value bets, betting even when you have thin value. You do not make outright bluffs into this player as he is a calling station, who is capable of calling quite outrageously.

Player B: VPIP 13 PFR 12 AF 5.5

This player is super-tight and quite aggressive, though not very aggressive. His high AF stems more from the fact that he is usually playing strong hands that perform well at showdown and will often be strong at the flop stage.

Most of the exploitation of this player takes place preflop by constantly stealing from him. Postflop, you are going to need to exercise caution and only make plays which have clear value. He does not favour calling bets, so when you do see him flat-call, this is an alarm bell and could indicate he is holding a very strong hand.

Actually, his bets and raises will often be weaker than his calls, but due to his tight range, you need to have a good holding to justify playing back at him. It is not easy to exploit this player postflop.

Player C: VPIP 21 PFR 14 AF 2.7

This player is far more balanced. I would not look to alter my default plays from this information. If you happen to have thousands of hands on him, you can look at more detailed postflop statistics, breaking information down street by street. C-bet and Fold to C-bet converge relatively quickly.

If you don’t have a good sample size, don’t get influenced by the statistics. An AF of 2.0 to 3.0 is relatively normal for this type of VPIP/PFR.

Player D: VPIP 31 PFR 15 AF 11.4

Now we have a player who really dislikes calling and is probably far too aggressive postflop. Any flat-call from this player is a huge alarm bell. He probably checks and folds a decent percentage too, so don’t mistake his high AF for pure aggression.

When he plays a hand postflop it is nearly always with a bet or a raise, so there will be draws and bluffs in his raising range. You can call him down much lighter than you can a standard player, depending on the strength of your hand, your position and all the other postflop factors.

When you bet into him, you should know how you are going to react to the raise. When your holding is marginal, you may want to play more passively than normal and be prepared to make some hero calls.

In summary:

·         AF has nothing to do with checking and folding

·         AF measures how much a player likes to call postflop

·         Though becoming less popular, AF is still a very useful statistic

·         Always measure postflop aggression in conjunction with VPIP/PFR and preferably one of the other 2 aggression stats

2: Aggression Percentage (Agg%)

Agg% differs from AF in that it brings checks into the equation. This is good, but does complicate matters somewhat.

Checks can mean a lot of different things in a lot of different scenarios. A check is not always a weak action and could be a precursor to an aggressive action e.g. a check-raise. For this reason, the statistic is imperfect. If all players’ checks meant the same thing, it would work better.

A player’s relative position and the number of postflop opponents will often influence how likely a player is to check in any given scenario, so when you are examining a particular spot, make sure you think about the basics and not just your opponent’s agg%.

On the plus side this statistic does contain more information than AF. It will also converge faster as a result. After a few hundred hands, you should be able to see roughly how aggressive your opponent is and use it to build a general profile for the opponent. This is partly why it is more popular in the modern game.

Mostly the AF will tally with the Agg%, so if you use both statistics, an AF of 2.5 will generally have an Agg% of around 33% (normal). When you notice a huge deviation (remember I’m talking about sample sizes in excess of 200-300 hands), that will tell you something about how often your opponent checks and how often he calls.

If the Agg% is high, but the AF is low, the player likes calling, but rarely checks. More usefully, when the Agg% is low, but the AF is high, the player likes checking, but rarely calls.

You should be able to use that information to help your decision-making.

For HM2 users, you can use these 2 statistics together and get used to how they correlate. As with most statistics, when you see something surprising, that is when it useful.

In summary:

·         Agg% includes checks in the equation

·         Agg% is a useful snapshot (after 200+ hands) of how aggressive a player is postflop

·         Always measure postflop aggression in conjunction with VPIP/PFR

Are you detecting some repetition to my advice? Good.

3: Aggression Frequency (AFq)

PT3 users should be using this statistic, which makes more sense than Agg%, but is unavailable in HM2.

Instead of adding checks into the mix, it adds folds. Earlier I expressed dissatisfaction at checks being included as part of the passive denominator, but including folds instead builds an optimum all-round postflop aggression statistic.

As an HM2 user, I am not going to discuss this statistic in detail as I do not have personal experience using it. I see it as a feather in PT3’s cap.

I like the fact that this statistic ignores checks and focuses on truly aggressive actions against truly passive actions. The result ought to be accurate and hugely useful information.

In summary:

·         Afq includes folds in the equation

·         Afq is the optimum measure of postflop aggression

·         Always measure postflop aggression in conjunction with VPIP/PFR

Well, you knew it was coming.

Final Thoughts

For those of you who do play with samples of over 1000 hands on opponents, you can break down the aggression stats by street and this can reveal even more pertinent information (many players are aggressive on the flop, but passive on the turn and river).

If you do not have a good sample size on an opponent, do not use anything other than VPIP/PFR. You can alter your HUD settings to only show numbers once a certain sample size is reached. If you have fewer than 10 examples of something, do you really want to base your decisions on that?

Postflop play is complicated. I know, I wrote a book on it! In general terms, when your opponent is too passive, you should be active, make bets, perhaps use a small-ball tactic, prod and pry and make him fold, whilst respecting his bets.

If an opponent is too aggressive, sit back more than usual, but don’t stop betting altogether. Be prepared to call with thin value and assess his range carefully.

What do you think? Leave a comment and I will respond.