See also
You may have heard before that hand values change based upon the number of players in the hand. For instance, small suited connectors such as 65s play well against a field but play poorly heads-up. On the other hand, a hand like A7 offsuit plays poorly against a large field but heads-up it plays quite well because it will often win unimproved. In other words, if you are heads up with A7 offsuit, you may win with ace-high if neither of you make a pair. To more easily understand how hand values change, it is helpful to mink about a concept called equity.
Let's say we play a bizarre version of Hold'em in which everyone calls all the way to the river regardless of what they hold - you know, like a $2/$4 game. If you are playing in a 10-handed game like this you should win, on average, 10% of the hands. A random holding men would have 10% equity. The whole idea behind starting hand requirements is to play those hands which have a better man average equity and to fold preflop those hands which have a negative equity.
While it's unlikely that everyone would stay all the way to the river regardless of my cheap shot against $2/$4 games, the value of hands and how they change depending upon the number of players in the game is still of great value to understand. Take for instance our example above of 6/5 suited. In a 10-handed game it has equity of 11.93%, which means that it has a positive equity since the average equity for a random hand is 10%. In a heads-up match however 6/5 suited doesn't fair as well only claiming 43.08% equity when a random hand heads up has 50% equity. 6/5 suited then has a positive equity with many people seeing the flop but loses equity the fewer players in the hand until it finally has a negative equity.
Now let's look at our other example, A/7 offsuit. In a 10-handed game it has equity of 9.93%, which means that it has a negative equity but heads up it has a positive equity coming in at 58.78%. Here's a hand which you would do well to throw away preflop unless the game is short-handed in which case you may even want to raise with it.
Numbers like mis have limitations. They don't take into consideration how well you play or how well your opponent plays. Too, they are based on results, which are run hot and cold; meaning they assume that all players will stay in all the way to the river - showdown poker. Despite these limitations though, the numbers have value. You can see how a hand stacks up against its peers and how they change values as the game becomes short-handed or fills up. You can also see how its equity increases or decrease against multiple players and poker strategy based on that data.
For instance, the ever-troublesome J/J has a 19.37% equity 10-handed against random hands. The average equity of a hand played 10-handed is 10% and so this is a 93.7% increase over the average equity. Not bad. How does J/J fare five-handed? Five-handed JJ has equity of 40.31% and an average hand has equity of 20%. This is a 101.6% increase over the average equity.
Based on these numbers, would you prefer to play J/J against 10 players or five? If each of ten players put $10 into the pot while you are holding J/J there would be $100 in the pot and your equity would be 19.37% of this or $19.37. If each of five players put $10 into the pot while you were holding J/J mere would be $50 in the pot and your equity would be 40.31% or $20.16.
Therefore, if you are in a game where everyone is typically calling unraised pots preflop but a raise would thin the field to about five players, you may choose to raise.
