Frequently Asked Questions
How are MLB playoff odds calculated?
BaseChaser runs 100,000 Monte Carlo simulations of the remaining MLB season. Each simulation uses team Elo ratings (derived from projected WAR and actual game results) to determine game-by-game win probabilities. At the end of each simulated season, we count how often each team made the playoffs. The odds you see are the percentage of simulations where that team clinched a playoff spot.
How many simulations are run?
Every update runs 100,000 full-season simulations. This gives a margin of error of roughly +/- 0.3% for any given team's odds.
What is the K-factor?
The K-factor controls how quickly Elo ratings respond to new results. BaseChaser uses K=2 with a 30-70% win probability clamp — no team gets worse than 30% or better than 70% chance in any single game.
What are game scenarios?
The 'If [Team] wins' and 'If [Team] loses' percentages show what a team's playoff odds would be if that specific game went a certain way, with all other games simulated normally. The delta shows the change from current baseline odds.
What is best case / worst case tonight?
The most and least favorable playoff odds outcomes across all simulations for the best and worst combination of tonight's results for that team — accounting for rival games, not just their own.
What does 'bubble' mean?
Teams with playoff odds between 5% and 95% — not clinched, not eliminated. Where every game matters most.
Is this for betting?
No. BaseChaser is for entertainment only. Do not use this for gambling decisions.
← Back to playoff odds | How to Use BaseChaser | Methodology