The terms,
defined right.
Sports analytics has a vocabulary problem. Half the industry uses the same words to mean different things, and most online definitions confuse market mechanics with actual statistical concepts. This glossary is rigorous, source-cited where possible, and written for operators and bettors who need precision.
Kelly CriterionKelly Stake
Mathematically optimal bet-sizing rule for any wager with a known edge. Given an estimated win probability and the offered odds, returns the fraction of bankroll to stake.
Read definition →Closing Line ValueCLV
The difference between your bet's price and the price the same market closed at. The most reliable indicator of long-run predictive edge.
Read definition →Implied ProbabilityMarket-Implied Probability
The probability of an outcome implied by its quoted odds. The building block of nearly every other betting calculation.
Read definition →CalibrationProbability Calibration
A property of a predictive model whose stated probabilities match observed frequencies in the long run. The single most important quality property for any betting model.
Read definition →VigorishVig, Hold, Juice
The bookmaker's built-in margin on a market, expressed as the share of every dollar wagered that the book expects to retain. The reason raw implied probabilities sum to more than 100%.
Read definition →Sharp MoneySharp Action
Money wagered by professional bettors and syndicates whose decisions tend to anticipate market movement. The flow that bookmakers respect and recreational bettors usually fade.
Read definition →Expected ValueEV
The probability-weighted average outcome of a bet, expressed as a per-unit dollar return. The single number that tells you whether a wager is profitable in the long run.
Read definition →Walk-Forward ValidationWalk-Forward Backtesting
A model evaluation method that simulates real-world deployment by training on historical data up to a point in time and testing on subsequent unseen data, then advancing the cutoff and repeating. The honest test of whether a sports model's performance survives outside the training set.
Read definition →Monte Carlo SimulationMC Simulation
A numerical method that estimates probability distributions by running thousands of randomized trials and aggregating the results. The core engine behind every modern sports prediction model that produces probability distributions rather than point estimates.
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