The Path to a Championship: How the Odds Change as the World Series Progresses

The World Series is now split at one game apiece. How does that alter the Dodgers' and Astros' path to a championship? Glad you asked!

The Astros and the Dodgers will head into Game 3 of the 2017 World Series on Friday night in Houston after an electrifying first two games. History suggested that a lot rode on the first game of the series, but now that the series is knotted at one, does one team have a decided edge?

A Sports Illustrated analysis of 108 past Fall Classics, using the treasure trove of baseball data at Retrosheet.org, found that the winner of the first game goes on to win the series 64% of the time. While that’s hardly a death sentence for the losing team, the odds of a comeback quickly grow slim as one team falls behind. Teams that have lost the first two games, for example, have rallied back to win the series only 10 times out of 52 such setbacks.

The following interactive displays the World Series as a “decision tree” that progresses from game one to every possible outcome, displaying the odds that a team will win based on the record at each intersection. The odds are drawn from 108 World Series contests dating back to 1905, excluding four seasons in which Major League Baseball switched to a best-of-nine format.

As one can see, the odds get slimmer the deeper the series gets. No team has ever come back from a 0–3 deficit to win four straight games, though it’s been known to happen in the league championship series, as any Red Sox fan will remind you after the 2004 ALCS. Out of 45 teams that have fallen to 1–3 in the World Series, only six have come back to win—as any Chicago Cubs fan will remind you after last fall.

There are many routes to winning four games—35, to be precise—and the order of wins and losses may matter. A 2–2 record can feel different if it’s a team that, say, came back from 0–2 after moving to their home stadium, rather than teams that have alternated wins and losses. Even after 108 years, there isn’t enough data to know whether records are “path dependent,” as the term goes.

And of course, the historical record is only a guidance, not a destiny. Baseball is a game of firsts, and every season many things happen that have never happened before. It’s one of the game’s great virtues.

Source

The information used here was obtained free of charge from and is copyrighted by Retrosheet.  Interested parties may contact Retrosheet at "http://www.retrosheet.org".