Line Movement Dataset: how much betting lines actually move (11.7M odds snapshots)
Description
Aggregate measurements of pre-match betting line movement across 13+ sports and three market types, built from 11.7 million odds snapshots recorded at roughly hourly cadence across 52 online bookmakers and 22 competitions, 29 June – 3 August 2026. To our knowledge the first open, multi-sport measurement of line movement magnitude. Files: (1) betbetter_line_movement_h2h.csv — open-to-close movement of de-vigged head-to-head probabilities, one row per sport, including the signed drift of the opening favourite; (2) betbetter_line_movement_points.csv — movement of the quoted spread/total line itself, one row per sport × market type; (3) betbetter_distance_to_close.csv — mean absolute gap to the closing price by sport × time-to-start bucket. Headline findings: movement is sport-specific by an order of magnitude — UFC/MMA lines move 2.76 probability points open-to-close (53% move >2 pts), AFL 2.52, WNBA 1.81, against MLB 0.60. Price discovery happens 1–7 days out: prices sit ~2.2 pts from their close 3–7 days before start but only 0.33 pts in the final six hours. Favourites systematically shorten toward the close (MMA +0.8 pts). AFL handicaps move 2.55 pts with 76% of lines changing, while MLB run lines are essentially static. Probabilities are de-vigged before measurement, so figures reflect price relocation, not margin change. Aggregates only: no odds, prices, bookmaker identities, teams, players or event identifiers; no underlying feed can be reconstructed. CC BY 4.0. Companion study: https://betbetter.world/studies/line-movement. Related: Bookmaker Margin Panel (doi:10.5281/zenodo.21755380), Market Calibration Dataset (doi:10.5281/zenodo.21764674).