Stack-to-Pot Ratio, Part 3: Rules of Thumb and Example

So what constitutes a "low" or "high" SPR? Or a "medium" one for that matter. And what kind of hands work best with each? Let's take a brief look:

• Low SPR: 1-7.  Good hands for low SPRs include overpairs, top pair, big overcards (e.g., AK), and bottom two pair type hands. In other words, these are the types of hands we don't mind getting it all in with if the stack sizes are low enough; i.e., we don't want to play big pots with these types of hands. 
• Medium SPR: 7-16.  Good hands for SPRs in this range include top two pair, sets, strong (nuttish) drawing hands, and made flushes and straights. These hands are obviously much stronger than the Low SPR hands, and are frequently (but not always) the best hand when you do get it all in.
• High SPR: 16+.  Good hands for high SPRs are sets, big combo nut drawing hands, and big flushes and the high-end of straights. Hands like these are almost guaranteed to win the pot, so the deeper the stacks the better.

Let's take a simple example to see how this all works:

You're in a $2/$4 NL cash game. You're new to the table and pick up Q♠Q♥ in the CO. Player A limps UTG, you make it $15 to go. Player C on the button calls, and Player A calls.  The pot on the flop after rake is taken out $50.

The flop is 2♣6♣9♥, which looks dry and light. Player A leads out for $20, you raise to $65, and then Player C pushes all-in. Player A folds. What should you do?

Answering this properly would (obviously) entail a full-up REDi analysis, and part of that process in the E-is-for-Estimating step in which we would calculate the SPR. To do this, we have to know what the effective stack size is (which was not given in the original problem statement). Here's four different scenarios:

1. You have $350 behind when Player C shoves his remaining stack of $100. The SPR is therefore $100/$50 = 2, which is considered Low. You have an overpair to the board with a low SPR, therefore you should call.
2. You have $350 behind when Player C shoves his remaining stack of $350. The SPR is therefore $350/$50 = 7, which is right on the cusp between Low and Medium. This means you have a judgment call to make based on other factors, such as the tendencies of your opponent to bluff shove, bet big with draws, etc.
3. You have $350 behind when Player C shoves his remaining stack of $900. The SPR is $350/$50, which is the same as the previous example. I.e., don't forget that SPR is calculated with the effective stack size, which is the smallest of the stacks in play. In this case it's your $350 stack.
4. You have $1000 behind when player C shoves his remaining stack of $1000. The SPR is therefore $1000/$50 = 20, which is High. Therefore you're not pot committed and don't want to go broke with a one-pair hand; this is an easy fold.

Something to note that SPR does not factor in is the amount of dead money in the pot. Frankly this has always bothered me, and I think that SPR can probably be improved upon by somehow including this. For example if Player A had put a big chunk of cash in the pot but then folded to Player C's shove, this certainly should be factored into your estimate of pot commitment. It doesn't, however, per the strict definition of SPR. Also, I think that other factors such as board texture, whether the pot is multi-way, etc. all need to go into determination of commitment, and not just SPR.

Okay, that said, SPR is the standard tool that is taught because it's so easy to use. More importantly, and as we'll see in the next installment, you can use SPR to help plan your commitment in the hand before you even get to the flop. SPR is an (im)perfect tool that allows you to do this.

On to Part 4...

All-in for now...
-Bug