 Total player rating is computed using linear weights, in which each event in a baseball game (for instance, a base on balls, a double or a stolen base) is assigned a value in runs.Each player then has a rating in Batting Runs, Pitching Runs, and Fielding Runs, usually adjusted for park and position, and the sum of these values is divided by 10 and is expressed as an offset in games from an "average" baseball player.Thus, a star player in a season might have been worth 6 games more than an average player, while a scrub might be 5 games below average.