Welcome to the new Win Expectancy Finder. There are a couple of things you should know.
  1. The games won and expectancy percentage are always given from the perspective of the home team.
  2. You can choose a range of years from 1977 - 2006 (except 1999) I'll be adding more as time goes on.
  3. The score differential is given from the perspective of the batting team. I guess it's weird that one thing (the score differential) would be based on the batting team and another thing (the win expectancy) would be based on the home team, but it was an organic process, and organic processes are messy.
  4. Score differentials of -7 and +7 include everything beyond those values. All the situations with teams up by 8, 9, 10, etc. get rolled into the "7" data. Just like all the extra inning data gets lumped together in "+". This may change, but I'll let you know if it does.
Thanks to Phil Birnbaum for the orginal inspiration to make this, and Retrosheet for the data.

As always, email me with any questions or mistakes found.
2007-10-14: Wow. The more I've been forced to deal with MLB.com's website and their customer service team, the more horrible it reveals itself to be.
2007-04-19: Now you get links to results you look up. Handy for messageboard arguments.
2007-03-01: 1977 is here. There's now data from every regular season major league baseball game I've been alive for (except those played in that pesky 1999 season).
2007-02-27: I've added data for 1978 and 2006 today. The 1978 home team winning percentage for all games seemed a little fishy (over 57%!), but I checked it by hand. 1978 was a good year to root for the home team.