Sabermetrics

Sabermetrics is the empirical analysis of baseball, especially baseball statistics that measure in-game activity. The term is derived from the acronym SABR, which stands for the Society for American Baseball Research. It was coined by Bill James, who is one of its pioneers and is often considered its most prominent advocate and public face.

General principles

The Sabermetric Manifesto by David Grabiner (1994) begins:

It may, however, attempt to settle questions, such as, "Was Willie Mays faster than Mickey Mantle?" by establishing several possible parameters for examining speed in objective studies (how many triples did each man hit, how many bases each man stole, how many times he was caught stealing) and then reaching a tentative conclusion on the basis of these individual studies.

Sabermetricians frequently question traditional measures of baseball skill. For instance, they doubt that batting average is as useful as conventional wisdom says it is because team batting average provides a relatively poor fit for team runs scored. Sabermetric reasoning would say that runs win ballgames, and that a good measure of a player's worth is his ability to help his team score more runs than the opposing team. This may imply that the traditional RBI (runs batted in) is an effective metric; however, sabermetricians also reject RBI, for a number of reasons. Rather, sabermetric measures are usually phrased in terms of either runs or team wins. For example, a player might be described as being worth 54 offensive runs more than a replacement-level player at the same position over the course of a full season, as the sabermetric statistic VORP can indicate.