Backgammon Equity

Equity is often used to describe how good or bad your position is.

The dictionary definition of "Equity" is the value of ownership. In backgammon, it means the value of your game.

Let's say you're in a position in a game where you are 75% likely to win a single point, 10% likely to win a gammon, and 15% likely to lose (you can't lose a gammon). Your "equity" is .75 + .10 * 2 - .15, or .80. If you were playing for a dollar a point and someone came along and said "I want to take over your game," you would expect him to pay you 80 cents as the fair price for your game - your value of owning the advantage in the game, your "equity." If one move leaves you with equity of +.30 and the other with equity of +.15, the first move would be said to be +.15 better than the second.

There is also a concept of "match equity." This is the odds of winning the match. Let's give a simple example. You are leading a 3-point match 2-0, and it's the Crawford game. Your opponent needs to win two games in a row to win the match. (This assumes that if he wins the first game without winning a gammon, he will double you immediately in the second game.) Since he needs to win two in a row, his odds are .5 * .5, or 25%. Your "match equity" - your odds of winning the match - is .75.