How important is the Go-Ahead RBI?

It's been years since Major League Baseball dispensed with the Game-Winning RBI as an official statistic, but STATS, Inc. continues to track the Go-Ahead RBI -- that is, any RBI that gives a team the lead at any time during the game. Now, that may not sound quite so important if a GARBI comes in the early stages of a given contest, and as you would expect, the incidence of ultimate victory in a game increases the later a GARBI is recorded. A go-ahead run in the ninth inning or in extra innings virtually assures a win.

But you may be surprised to find that last year, teams that went ahead in the first inning of a game ended up winning nearly two-thirds of the time. Here are the winning percentages for all teams in 2002 after they took the lead in a particular inning: