E - Poker Terms
Your mathematical share of a pot, based on the amount in the pot and your chances of winning it. If the pot is $100, and your chances of winning are N%, then your equity in that pot is $N. If the pot is $200, your equity is $2N.
See expectation.
Expectation is the rate of profit (or loss) you would expect to make if there were no variance, or on average over a very large number of trials. A positive expectation poker player is one who, due to an advantage in poker skill over his/her opposition, will earn money in the long run. A negative expectation poker player is someone you want at your table.
Just about anything with a numerical outcome has an associated expectation. A positive expectation situation is one in which you will, in the long run, expect to make money. A positive expectation bet is a bet that would, if you made it a sufficient number of times in nearly identical circumstances (from your perspective), earn you a profit. Such a bet is said to have positive expectation.
Note that a player's overall expectation is not a rigid constant. You may be a positive expectation player overall, but perhaps not at certain tables, or when you're in a particular emotional or other state.
Expectation is closely linked (essentially identical) to "expected value," or EV, a mathematical concept best illustrated by the following example. If you have a 50% chance of winning (and a 50% chance of losing) a $100 pot, your expectation is $50, even though you will definitely not win exactly $50. This example also illustrates variance.
Positive expectation is sometimes abbreviated as +EV, and negative expecation as -EV.
I finally stood up when I realized that it wasn't just back luck, I was a negative expectation player at the table.