Part of playing winning poker involves learning to respect the action that’s preceded you. For example, if someone has already bet or raised the pot, you should probably continue with fewer hands than you would’ve if everyone had folded to you; this is known as the ‘gap’ concept. Introduced by respected and renowned poker authority David Sklansky in his book Tournament Play for Advanced Players, the gap concept holds that it takes a superior hand to call a raise than it takes to make the initial raise itself.
This unique concept is not Texas Hold'em specific and can actually be used in most variations of poker that feature an initial betting round.
The Gap Concept: Defining the Distance
The 'gap', as Sklansky calls it, refers to the space between the value of the hand of the person who raised and the value of the hand of the player who called. Certain factors will cause the gap to increase and other factors will cause it to decrease.
Here’s what we mean:
Type of Player.
The basic premise behind gap concept and player type is that you don't necessarily require the nuts to call a raise against a loose player but you will require a decent hand to call a raise against a tight player. As such, the gap will get larger if you're up against a tight opponent (because you will need a better hand) and it will get smaller if you're up against a looser opponent (because you are more likely to succeed with a less than stellar hand).
Number of Players.
When there are more players in the hand, the gap increases because the likelihood that you have the best hand decreases.
A raise from late position won't show as much strength as a raise from an early position (EP). When someone raises EP, there's a pretty good chance that the person has a good starting hand (think AA, KK, QQ, JJ, AK, TT, AQ, AJ). So, following this logic, it would stand to reason that an EP raise would increase the gap, since it is likely that your opponent's hand is pretty solid.
The gap concept is basically another way to think about evaluating the merits of making a bet. It shows the perks of aggressive play given the right circumstances, including position, hand selection, and opponents. Like many poker strategies and theories, gap concept works best when used in tandem with other value determining strategies, like outs, pot odds, expected value and fold equity. In other words, while the gap concept stands alone as a solid theory, it works best as a part of your overall strategic armour.