Printer-friendly

August 22, 2007

The Big Picture

Re-calculating the Save

by David Pinto

Two weeks ago I proposed a new way of defining saves. The save had been instituted to reward the evolving role of the fireman, the reliever who came into a game in a tight situation to save the day. However, today's closer rarely faces a game on the line situation, unless he creates it himself. The rule defined the role over the years, turning saves into relatively passive activities. It's time to refine the rule, or introduce a more active statistic to move the closer back to the role intended, the pitcher who saves the day.

Which is where I came up with my proposal--rather than awarding saves to the person who finishes the game, the reward goes to the pitcher with the best performance in terms of increasing the team's chance of winning while also meeting a threshold increase of 0.1. Unlike the 1970s, when baseball defined the save rule, we now know the probability of a team winning at every point in the game. Given the score, base situation, and inning when the reliever enters and leaves the game, we can tell how much he helped shift the probability toward winning.

That was the theory. This week's column puts the theory into practice to find out how the proposed rule changes the number of saves awarded and which pitchers benefit and decline under this scheme. The play-by-play data used comes from Baseball Info Solutions and covers 2002-2006. William Burke and Keith Woolner supplied the Win Expectancy data, and I'm grateful for their help.

For every game in that time frame, queries determined the last event in a game in which a team was tied or trailing. Relievers entering the game after that point were eligible for a save, provided they did not get the win. For each reliever eligible, the inning, half-inning, outs, base situation, and score difference was recorded both for the event in which he entered the game and the event in which he left the game. Queries then calculated the win expectancies for both points, and the difference became the score for the pitcher for the game. If the score was...

• greater than 0.1 and the highest score for the game
• or greater than or equal to 0.3