Name of the Game: Do Statistics Confirm the Labels of Professional Baseball Eras?

Abstract

A game defined and measured by hitting and pitching performances, baseball exists as the most statistical of all sports (Albert, 2003, p. ix). Probably more than any other sport, the game's present is couched in references to its history. Professional baseball has endured many changes (both overt and subtle) in rules, equipment, stadium structures, and competitive strategy over the course of its history. Because of such shifts, the modern era of Major League Baseball (MLB) has been segmented into six distinct eras (Lombardi, 2006): Dead Ball (1901-1919), Live Ball (1920-1941), Integration (1942-1960), Expansion (1961-1976), Free Agency (1977-1993), and Long Ball/Steroid (1994-2005). This study runs through the 2011 season and adds a seventh era, labeled "Post-Steroid" (2006-present).

The purpose of this research was to determine how the names and/or characteristics/perceptions associated with the actual offensive outputs of each era of MLB corresponded with the statistical realities related to each era's On-Base Plus Slugging Percentage (OPS), beginning with the 1901 season and MLB's Modern Era. The study's sole focus was the effect of team OPS to determine how hitting and pitching contributed to team winning percentage in each era.

Results were segmented by each defined era to determine any significant differences between the eras. Multiple regression and ANOVA were used to determine if perceptions and realities for each era's offensive output aligned descriptively. Results showed that perceptions for five of the seven eras matched statistical realities, while perceptions of two eras did not. Results also showed significant statistical differences between the defined periods and illustrated how offensive output defined each era.