Bracketology is the process of preicting the field of the NCAA Basketball Tournament, named as such because it is commonly used to fill in tournament brackets for the postseason. It incorporates some method of predicting what the NCAA Selection Committee will use as its Ratings Percentage Index in order to determine at-large (non-conference winning) teams to complete the field of 65 teams, and, to seed the field by ranking all teams from first through sixty-fifth. ESPN's Joe Lunardi is the inventor of the term "bracketology", starting first as the owner and editor of the Blue Ribbon College Basketball Yearbook and ending up with a gig as the resident bracketologist on ESPN.