An example of why I don't like the PT aggression factor

[MaxPower]

PartyPoker - $15/$30 - 8 players

MP2 is 55/1.8/.55 over 1150 hands. These stats spell calling station right?

Hero is SB with K[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/club.gif[/img]

PreFlop
<font color="blue">UTG folds</font>, <font color="blue">UTG+1 folds</font>, <font color="blue">MP1 folds</font>, <font color="green">MP2 Calls</font>, <font color="blue">CO folds</font>, <font color="red">Button RAISES</font>
<font color="red">Hero RAISES</font>, <font color="blue">BB folds</font>, <font color="green">MP2 Calls</font>, <font color="green">Button Calls</font>

(3 players) FLOP: 8[img]/images/graemlins/heart.gif[/img] Q[img]/images/graemlins/club.gif[/img] 2[img]/images/graemlins/diamond.gif[/img] ( Pot Size: 5 BB )
<font color="red">Hero BETS</font>, <font color="red">MP2 RAISES</font>, <font color="blue">Button folds</font>
<font color="red">Hero RAISES</font>, <font color="red">MP2 RAISES</font>
<font color="green">Hero Calls</font>

(2 players) TURN: 2[img]/images/graemlins/spade.gif[/img] ( Pot Size: 9 BB )
<font color="red">Hero BETS</font>, <font color="red">MP2 RAISES</font>
<font color="green">Hero Calls</font>

(2 players) RIVER: Q[img]/images/graemlins/diamond.gif[/img] ( Pot Size: 13 BB )
<font color="green">Hero checks</font>, <font color="green">MP2 checks</font>

Final Pot:13 BB

Results in white below:
<font color="white">SB shows:KsKc,two pairs, kings and queens</font>
<font color="white">MP2 shows:9c5c,two pairs, queens and twos</font>

How many calling stations play like this? This is not an unusual hand for this guy.

[DcifrThs]

AF is relative.

55% of his hands are played. lots of trash.

he checks or calls ON AVERAGE about 1/2 the amount that he bets or raises over the total # of observed hands.

a 55vpip is almost never a calling station.

-Barron

[gonores]

[ QUOTE ]
AF is relative.

55% of his hands are played. lots of trash.

he checks or calls ON AVERAGE about 1/2 the amount that he bets or raises over the total # of observed hands.

a 55vpip is almost never a calling station.

-Barron

[/ QUOTE ]

Well said.

[MaxPower]

[ QUOTE ]
AF is relative.

55% of his hands are played. lots of trash.

he checks or calls ON AVERAGE about 1/2 the amount that he bets or raises over the total # of observed hands.

a 55vpip is almost never a calling station.

-Barron

[/ QUOTE ]

Checking does not factor into the aggression computation except where he checks and then calls. It is:

(Bet% + Raise%)/Call%

So I think .55 means that he calls twice as often as he bets or raises.

Two players with the same VP$IP and AF aggresion can have very different styles. For example you can have a AF aggresion factor of .5 if you bet or raise 25% of the time and call 50% of the time. You can also have a .5 if you bet or raise 10% of the time and call 20% of the time.

Now I do think we can make use of this information, but it is a problematic measure. I think it would be much more useful if we just had the numerator and denominator as seperate stats.

[bobbyi]

[ QUOTE ]
Two players with the same VP$IP and AF aggresion can have very different styles.

[/ QUOTE ]
No kidding. That's why there are stats other than VPIP and AF. Any two numbers isolated from the rest of someone's game is not going to be enough to describe someone's game, otherwise we would only have two stats available and be done with it. Think about how large the space of playing styles is at holdem. Why would you expect it to be only two dimensional? Most stats (including AF) in isolation are not that meaningful.

It's like if you only looked at one of the cards on the flop when deciding what to do. It wouldn't work very well. But the right conclusion to draw wouldn't be that you should stop looking at the flop at all.

[MaxPower]

[ QUOTE ]
[ QUOTE ]
Two players with the same VP$IP and AF aggresion can have very different styles.

[/ QUOTE ]
No kidding. That's why there are stats other than VPIP and AF. Any two numbers isolated from the rest of someone's game is not going to be enough to describe someone's game, otherwise we would only have two stats available and be done with it. Think about how large the space of playing styles is at holdem. Why would you expect it to be only two dimensional? Most stats (including AF) in isolation are not that meaningful. It's like if you only looked at one of the cards on the flop when deciding what to do. It wouldn't work very well. But the right conclusion to draw wouldn't be that you should stop looking at the flop at all.

[/ QUOTE ]

I don't expect to be able to use 2 numbers to describe someone's game.

I agree that you don't use any one statistic in isolation.

Most of the stats in PT have very simple interpretations. The are just simple percentages. Someone with a high VP$IP plays a lot lot hands. Someone with a low VP$IP plays very tight. I can say with certainty that a player with a VP$IP of 20 players tighter than a player with a VP$IP of 30 (assuming a decent sample size). That is what I want out of a measurement.

The problem with the aggression factor is that I cannot say for certain that someone with an AF of 1 is more aggressive than someone with an aggresion factor of .5 (even if their other stats are the same). It is an issue of measurement validity.

Many of us find the aggression factor useful even though it is not perfect. But why should we settle for that when there may be a better way? I would rather have a less ambigous measurement even if it means I have to think about more things. Looking at the numerator and denominator of the equation seperately would be preferable to me.

[sammy_g]

Have you posted this at the PokerTracker forum? Because I agree, but it isn't likely Pat will see your post here.

[bobbyi]

[ QUOTE ]
Most of the stats in PT have very simple interpretations. The are just simple percentages. Someone with a high VP$IP plays a lot lot hands. Someone with a low VP$IP plays very tight. I can say with certainty that a player with a VP$IP of 20 players tighter than a player with a VP$IP of 30

[/ QUOTE ]
The reason you have "certainty" with the preflop stats is that they aren't dependent on things that happened earlier in the hand. Postflop stats are dependent on how one plays preflop, so they will never be meaningful by themselves in the same way as vpip whether they are percentages or not. For example, went to showdown is a simple %. However, a guy with a vpip of 95 and a wsd of 30 is going to showdown much weaker hands than a guy with a vpip of 12 and a wsd of 30, even though it is a simple percentage. So that alone is not the entire difference between AF and VPIP.

The reason AF is tough to interpret is that there are usually three possible actions postflop: bet/ raise, call or fold. But AF is only the ratio between bet/ raise and call. So without knowing how often the guy folds, you don't know the real percentages. I see your point there. But using other stats, you can get a good picture of how often he folds postflop, so combining that with his AF will give you a good picture of his bet/raise and call percentages. You are right that it might be simpler if (bet %/ call %/ fold %) were commonly used instead of a combination of AF and showdown stats, but they still give the same information (taken together), even if in a slightly convoluted way.

[DrSavage]

My example:
Villain is 62.31/0/0.25
Let's say i don't catch a set on river, would you call a river donkbet knowing he's 0.25 AF?

Party Poker (6 max, 6 handed) converter

Preflop: Hero is Button with 8[img]/images/graemlins/heart.gif[/img], 8[img]/images/graemlins/club.gif[/img].
<font color="#666666">UTG calls, MP calls, Hero raises, 3 folds, UTG calls, MP calls. </font>.

Flop: 9[img]/images/graemlins/club.gif[/img], 6[img]/images/graemlins/heart.gif[/img], J[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
UTG checks, MP checks, Hero bets, UTG folds, MP calls.

Turn: A[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
MP checks, Hero bets, MP calls.

River: 8[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
MP bets, Hero raises, MP calls.

MP shows K[img]/images/graemlins/spade.gif[/img] Q[img]/images/graemlins/spade.gif[/img] (high card ace)
Hero shows 8[img]/images/graemlins/heart.gif[/img], 8[img]/images/graemlins/club.gif[/img] (three of a kind, eights)

Edit: converter has butchered the hand for some reason so i had to put in the action myself hence the weird formatting.

[mike l.]

scary stuff. great posts guys. im done with the AF stat.