Over/under 2.5 goals asks one question of a match: do both teams' goals add up to three or more, or two or fewer? This page explains why the line sits at a half-goal, what a typical league baseline looks like as a range, and what actually moves a match total — attack and defence on both sides, tempo and shape, and what the match is worth, with weather and rest as caveats rather than drivers.
It also walks through how a Poisson-family goals model, with the Dixon-Coles adjustment, turns expected goals into an over-2.5 probability, and how a decimal price becomes a probability once the bookmaker's margin is removed. PredictionPitch publishes its own over-2.5 number next to the market's, graded against the closing line.