Value in the Lines

A common question that arises when betting on baseball, is what constitutes a good line? Most of the time (though the Yankees were well over average in 1998, and the Marlins below) baseball teams will win between 40% – 60% of their games. The baseball bettor must determine what they believe are the chances of a team beating another in a given situation, and then relate that to what- price is being given by the bookmakers.
The following is a breakdown of what percentage of plays at a given price must win, just for a bettor to break even:

Underdog

Favorite

Line % Needed to win Line % Needed to win
-110 52.4 -110 52.4
Even 50.0 -120 54.6
+110 47.6 -130 56.5
+120 45.5 -140 58.5
+130 43.5 -150 60.2
+140 41.7 -160 61.7
+150 40.0 -170 62.9
+160 38.5 -180 64.5
+170 37.0 -200 66.7
+180 35.7 -220 69.0
+200 33.3 -240 70.4
+220 31.3 -260 72.5
+240 29.4 -280 73.5