The World Series is decided in a best-of-seven format, so a team needs to win 4 games to claim the championship. The series can last anywhere from 4 to 7 games, depending on how quickly a team reaches four wins. Key points

• Shortest possible: 4 games (a sweep).
• Longest possible: 7 games (goes the distance).
• If you’re looking at historical patterns, teams leading 1–0 or 2–1 tend to win roughly two-thirds of the time when they’re ahead, while teams coming from behind have a smaller chance to finish the comeback, with larger gaps (2–0 or 3–1) making a win more likely for the leader.

If you’d like, I can tailor this to a specific World Series (year, teams, or current format) or compute the probability distribution of series lengths under different per-game win probabilities.