Debating a Call on the River

I was recently playing in a home game with my new roommate and some of his friends, and I was taking a minute to decide whether to call a big bet on the river or not, when my roommate looks at me and says "just call or fold, what the hell is there to think about?"  I immediately thought "Wow, that's a pretty intensive question, where do I even begin?"

Now, he was obviously a fairly new player, but even so I see more experienced players rushing into decisions every day.  It got me thinking though, what do I really think about when I'm debating a call, fold, or raise on the river.  The simple answer is a lot of things.

I've made a lot of money making calls that look unbelievably stupid from the outside looking in.  Quite often, if someone looked at my hand and saw I was debating calling a bet on the river, they'd assume that I'm a terrible player.  Calling a bet on the river with 4th pair is generally a bad idea, but poker is not a game of generalities, it's a game of situations, and in that situation it might not be a bad idea.  Now to be fair, I've lost a decent amount of money by calling and losing in these situations, but the payoff has been far greater.  I'm not saying call every bet on the river of course, like I said, there's a lot to think about.

It begins with going over the history I have with the specific player.  What kind of player is he?  Agressive?  Passive?  Reckless?  Does he bluff a lot in these situations or is he the type of player who is usually going to check down.  While I already have a basic idea of how he plays, it's important that you keep revisiting it as players do not usually play the same way all the time.  Emotions and other things can dramatically alter someones play.  When going over my history with that player I put much more weight in his recent play than I do his play a couple hours, days, or weeks ago.

Next I replay the entire hand in my head.  What did he do pre-flop?  On the flop?  On the turn?  How does this compare to his play in previous hands?  Is the bet he made bigger or smaller than normal?  If he's been fairly passive most of the hand, what improvements could he have gotten from the river card?  If he's been fairly agressive most of the hand, what could he have that he wouldn't be scared of being beat?

Using that information, I try to figure out how likely he is to be bluffing.  Is it a 35% chance or only a 10% chance?  Then I compare that to the bet size in relation to the size of the pot.  If his bet is 10% of the pot, than there only needs to be a 10% chance he's bluffing for that call to be profitable.  For example, if the bet is $100 and the pot before was $900, and I believe there is a 10% chance he's bluffing, then it's a profitable call.  I'm going to lose the hand 9 times out of 10, but I'm only going to lose $100 each time I lose while the one time out of ten he is bluffing I'm going to make $1000 for a profit of $100 every 10 hands.

Of course, there are times when I'm not going to be able to reach a good decision through all these questions.  This is where I start my opponent down.  Typically, if your opponent looks up at you and sees you staring at him, and looks away, he's more likely to be bluffing.  But if he meets your gaze, he's more likely to have a hand.  If he never looks up at all, where is he looking?  If he's looking down at the pot, he's more likely to be bluffing, if he's looking away at something not related to the hand, he's more likely to have a hand.

As you can see, I ask myself a lot of questions in these situations, and that's why it sometimes takes a minute or two to come to a decision.  I'm not a savant by any stretch of the imagination, and I can't sift through all the information in a few seconds.  I'm also not going to let someone else's impaitence impact my decision.  I wouldn't try to rush you and force you into a bad decision.