SIGNAL LABS

Home Track Record Glossary Sign Up

Glossary

Plain-English definitions of the metrics, math, and concepts our model uses. Cross-linked, structured for citation, no jargon for jargon's sake.

MLB

Batting Average on Balls in Play — the rate at which a hitter's contacted balls (excluding home runs) become hits.

Fielding Independent Pitching — a pitcher rate stat built only from outcomes the defense cannot influence.

Weighted On-Base Average — a hitter rate stat that weights each offensive event by its actual run value.

Expected ERA — a pitcher's earned run average if every batted ball returned a league-average outcome.

Expected Weighted On-Base Average — wOBA recomputed using batted-ball quality instead of actual outcomes.

Statcast

The percentage of a hitter's batted balls with exit velocity of 95 mph or higher.

The percentage of a pitcher's swings against that result in a swing-and-miss.

Football

Defense-adjusted Value Over Average — a play-by-play efficiency rating relative to league baseline.

Expected Points Added — the change in expected scoring value from one play to the next.

NBA

Effective Field Goal Percentage — shooting percentage that credits three-pointers for being worth 50% more.

True Shooting %

Shooting efficiency including two-pointers, three-pointers, and free throws on a single scale.

Soccer

Expected Goals — the probability that a given shot results in a goal, summed across all shots in a match.

Betting Math

Closing Line Value

The difference between the odds at which a bet was placed and the final closing line.

The average profit or loss per bet given the probability of winning and the odds offered.

The sportsbook's built-in margin — the percentage by which implied probabilities exceed 100%.

Implied Probability

The probability of an outcome implied by its betting odds.

Kelly Criterion

A bankroll-allocation formula that maximizes long-run log growth of capital.

No-Vig Fair Odds

Implied odds after the sportsbook's margin has been stripped out, summing to exactly 100%.

Bets placed by recreational bettors — typically the larger share of ticket count but a smaller share of total handle from sharps.

Reverse Line Movement

When a betting line moves opposite to the majority of public money on the game.

Bets placed by professional or analytically-driven bettors known to historically win at scale.

A standardized stake size, typically 1% of bankroll, used to communicate bet size without revealing dollar amounts.

Ratings

A continuously updated rating system where each team's score moves based on results against opponents of known strength.

Regression to the Mean

The statistical tendency for extreme observations to be followed by less extreme ones closer to the population average.

Separate Elo ratings for the same player by playing surface — hard, clay, or grass in tennis; turf or grass in soccer.