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Glossary

Every term, in plain English. Search or filter by category.

34 terms
AUC
Model
How well a score ranks winners over losers. 0.5 = coin flip; the closing market is ~0.77. Trusting the Harness
Bankroll
Betting
Money set aside for betting — and only money you can lose. It governs every stake.
biasFit (zBiasFit)
Model
How well a horse’s style + post fit the day’s bias. Folds into the signal at a modest weight. Reading the Track
Calibration (ECE)
Model
Do horses we call 20% actually win 20%? Low ECE = honest probabilities. Trusting the Harness
Chaos race
Betting
A wide-open race where favorites are vulnerable — the best spot for exotics.
Class
Handicapping
The quality level a horse has competed at (purse/conditions).
Closing line
Odds
The final odds at post — the sharpest price in the market and the benchmark to beat.
CLV (Closing Line Value)
Value
Did the price shorten after you bet? Beating the close is the #1 leading indicator of skill. CLV
Edge
Value
Your win % minus the market’s implied %. Positive = value; it must clear a threshold to bet.
Exotic
Betting
A multi-horse bet (exacta, trifecta, superfecta). High variance, separate scorecard.
Fair odds
Value
The price that exactly matches your honest win probability. Beat it on the board → overlay.
Form
Handicapping
Recent results and trajectory — are the figures climbing or fading?
Generator
Model
Which strategy produced a bet (e.g. win-overlay, exotic). Lets you measure ROI by source.
Implied probability
Odds
Convert odds to a win %: 1 / (odds + 1) for to-1 odds. 4-1 ⇒ 20%.
Kelly criterion
Betting
Sizes a bet in proportion to its edge. Bet a fraction (¼) to tame the variance. Making the Bet
Morning line (ML)
Odds
The track handicapper’s opening odds — a guess, not the market. The live tote is the truth.
Overlay
Value
A horse the board pays MORE than your fair estimate — the only thing you bet. Overlays
Pace (E1 / E2 / LP)
Handicapping
How a horse distributes energy — early speed vs late kick. Drives pace-fit.
Pari-mutuel
Betting
Pooled betting: all winning tickets are paid the FINAL odds, regardless of when you bet. CLV
Post position
Handicapping
The starting-gate slot. Inside saves ground; outside can be an advantage on a biased track.
ROI
Betting
Profit per dollar staked — the bottom line. Pari-mutuel ROI is what unlocks live betting.
Running style
Handicapping
E (early/speed), EP/P (presser/mid), S (closer). Determines bias fit and pace.
Scratch
Handicapping
A horse withdrawn before the race. It drops out of the field and the odds reshuffle.
Signal
Model
The composite z-score blending speed/form/pace (and bias). What the model tilts the market by.
Speed figure
Handicapping
A single number rating how fast a horse actually ran (BRIS). The heaviest factor.
Takeout
Odds
The track’s cut of every pool (~15–20%). The house edge your skill has to overcome.
Tilt (γ)
Model
How hard the model leans on its signal vs the market. γ=0 is the pure market. The One Idea
To-1 odds
Odds
Profit per $1 staked. 4-1 returns your $1 plus $4. Used everywhere in this app.
Track bias
Track
The surface favoring a running style or post on a given day. A tailwind or headwind. Reading the Track
Underlay
Value
A horse priced shorter than fair — the crowd knows more than you. A pass. Overlays
Value
Value
Betting a mispriced price, not a “good horse.” The horse can lose and still be a great bet. The One Idea
Walk-forward / holdout
Model
Train on the past, test on a future the model never saw. The only honest backtest. Trusting the Harness
Win pool
Betting
Bets on the outright winner — the cleanest, most measurable edge.
z-score
Model
A value standardized within the race: 0 = field average, +1 = clearly above, −1 = below.
Glossary · Academy · Closebeat