About Diamond AI
Diamond AI is a quantitative MLB prediction engine. At its core is a logistic regression trained on 22,762 historical games, validated at 56.5% accuracy on a held-out season. Every prediction is driven by math, not opinion.
56.5%
Validated Accuracy
2,430 holdout games
22,762
Training Games
2015–2024 seasons
233K+
Historical Games
Retrosheet 1871–2025
0.243
Brier Score
0.25 = coin flip
Four layers, each adding measurable accuracy. The statistical model is the brain. Everything else is signal.
A logistic regression trained on 22,762 MLB games (2015–2024) using gradient descent. Validated on a completely held-out 2025 season: 56.5% accuracy across 2,430 games with proper confidence calibration.
Elo Rating Gap
Team power differential
Pitcher FIP Diff
Fielding-independent pitching
Park Factor
Run environment adjustment
Game Context
Day/night, home advantage
Every team has a live Elo rating updated after each game, seeded from Pythagorean win expectation. Every starting pitcher has a Power Index (0–100) built from ERA, xERA, WHIP, K/9, quality start rate, and innings depth — with recency-weighted trend detection.
The final prediction blends our statistical model (50%) with Vegas implied probability (50%). The market prices in information no model can capture — clubhouse dynamics, undisclosed injuries, late roster moves. We respect the line, then look for divergence.
Claude AI reads 18 data dimensions per game — Statcast metrics, bullpen fatigue, weather, confirmed lineups, platoon matchups, head-to-head history — and produces the score prediction and reasoning. The AI doesn't pick the winner. The model does. The AI explains why.
When we say 65%, we mean it. Calibrated on 2,430 holdout games.
| Model Confidence | Games | Actual Win Rate | Verdict |
|---|---|---|---|
| 50–54% | 994 | 53.5% | Calibrated |
| 55–59% | 830 | 54.7% | Calibrated |
| 60–64% | 357 | 56.9% | Calibrated |
| 65–69% | 190 | 72.1% | Underconfident ↑ |
| 70–74% | 55 | 76.4% | Underconfident ↑ |
Backtest: 2025 season holdout (2,430 games not used in training)
Diamond AI gets smarter every day. After each game is graded, the system recalculates Elo ratings, updates pitcher indexes, recalibrates confidence, and feeds corrections into the next prediction cycle. No manual intervention.
Retrosheet
233K+ game logs (1871–2025)
Lahman DB
Season stats, team records, pitching
Statcast
xERA, exit velo, barrel rate, xwOBA
MLB Stats API
Live scores, lineups, rosters
Vegas Odds
Moneylines, totals, run lines
Claude AI
Qualitative analysis & reasoning