MLB Methods

Independent baseball forecasts, current prices and a public record of model checks.

Which games qualify

We match The Odds API events to MLB’s official schedule using both teams and a start time within ten minutes. MLB game IDs distinguish doubleheaders. Only regular season (R), Wild Card (F), Division Series (D), Championship Series (L) and World Series (W) qualify. Spring training, exhibitions, All-Star games, postponed or suspended games, delayed starts, and unknown start times are excluded. Unconfirmed playoff matchups are not invented.

Price comparisons

Moneylines, run lines and totals refer to full games. We do not mix first-five-inning markets into them. Props cover pitcher strikeouts and outs, plus batter hits, total bases, home runs and RBIs. Margin removal needs both sides from the same book, event, player, market and line. Run-line pairs use opposite handicaps. Each book gets one vote in same-line consensus; duplicate conflicting quotes are withheld.

Market Watch compares an offer with at least three other paired books, excluding the quoted book itself. It identifies disagreement, not a validated expected profit. Integer lines can push; de-vigged market probabilities are conditional on a non-push result. Confirm your book’s listed-pitcher, participation, postponement and settlement rules before using a quote.

What goes into a forecast

Official MLB game-level box scores supply prior player and team outcomes. We use the previous season from August onward, including October, and the current season. We discard box-score season totals and compute every historical feature from earlier dates only. All games on a date share the same pre-date history, including doubleheaders.

Team features include the last 40 games of scoring and batting rates, bullpen runs per out, and bullpen pitches over the prior three days. Pitcher features include up to 15 starts, outs and pitch counts over the last five, strikeouts, walks, hits and home runs per batter faced, runs allowed and rest. Batter features use up to 60 games of plate appearances and event rates, recent starting-game opportunities and the published batting slot. Rates shrink toward fixed league-like priors when samples are small. Venue scoring uses up to 100 prior games, shrunk toward nine combined runs; it is not a fully isolated park effect.

From a projection to a probability

Each target compares a small gradient-boosted regression with a transparent rolling-rate baseline on a later calibration period. The lower mean-squared-error candidate supplies the mean. Count outcomes use Poisson distributions when dispersion is negligible and negative binomial distributions when variability is larger. Pitcher outs use a discretized normal distribution. Isotonic calibration adjusts the cumulative probabilities using the calibration period; a 2% raw-distribution component avoids absolute certainty in the tails.

Two team-run distributions form a full-game score matrix. Tied final scores are removed and the remainder normalized. That approximation prices moneylines, run lines and totals; it does not simulate every extra inning or every pitcher change. Displayed projections are the means of the final calibrated distributions, so they can differ from the raw regression mean.

Win and push probabilities are separate. At decimal odds D, expected return per dollar is P(win) × (D − 1) − P(loss). Fair American odds and the displayed probability edge use P(win) / (1 − P(push)), allowing comparison with a book’s break-even price. Model probability itself is the unconditional win chance. The model never uses current book prices as a feature.

How an offer becomes a Model Pick

The relevant regular-season or postseason market must pass the checks on Model Results. Both probable starters must be known and have at least three earlier starts; both teams need ten earlier games. A batter needs 50 earlier plate appearances and a unique match to a complete published starting order. MLB’s published order can still change before first pitch.

The game must start within 24 hours; the quote and model-input check must be no more than 90 minutes old. At least two books must have paired outcomes at the same line, and the evaluated quote itself must be paired. The line must fall within the tested range. We require at least 3% estimated return and a 3-percentage-point advantage over the quoted break-even probability. Discrepancies above 30% estimated return are withheld for manual review. We select the best available price and one offer per player, market and game. Different selected markets can still be correlated.

These are experimental model picks, not a proven profitable system. When a check fails, the board explains why. A forecast may remain visible for research while its pick eligibility is withheld.

Starters, batting orders and limitations

Probable pitchers come from the current official schedule. Published orders come from the upcoming game’s box score and are accepted only with nine unique original slots and no recorded game action. We do not invent a lineup or forecast an unmatched player. Historical evaluation uses the actual starter and original starting order because archived pregame announcements are unavailable; late scratches and lineup uncertainty are therefore not fully captured by the audit.

The model includes a postseason indicator and recent workload. Its prior-postseason audit is small. Handedness, forecast weather, injuries, umpires and explicit pinch-hit or playoff-hook decisions are not modeled. Those factors can invalidate an apparent edge. Check current availability and your sportsbook’s settlement rules.

Separate descriptive season context uses regular-season totals through yesterday’s Eastern date. This display excludes postseason stats; the game-level model history includes completed postseason games. ERA and K/9 use recorded outs: 5.2 innings is 17 outs.

Freshness and coverage

Automated runs refresh history and retrain when the daily cutoff or model code changes. Rolling features include completed games through yesterday Eastern; weights stay earlier than the calibration and test periods. The visible dates distinguish these two kinds of updating. Markets refresh twice daily; comparison quotes expire after 12 hours, model picks after 90 minutes, and all offers at first pitch. Open boards refresh every five minutes. A stale or failed model refresh withholds model picks while current market comparisons can remain available.

Prop requests cover the next 24 hours, capped at 20 games per run. Skipped games are reported. Early runs can have no hitter forecasts because batting orders have not yet been published. Season context expires after 36 hours or a failed statistics refresh. Forecast snapshots preserve the quoted price, inputs, model version and eligibility decision for forward review.

Sources

MLB schedule · MLB postseason · MLB statistics · The Odds API MLB coverage