Division I (or DI) is the highest level of intercollegiate athletics sanctioned by the National Collegiate Athletic Association in the United States.
"D-1" schools are the major collegiate athletic powers, with larger budgets, more elaborate facilities, and higher numbers of athletic scholarships. This level was once called the "University" division of the NCAA in contrast to the "College" division; this terminology was replaced with the current numeric (I, II, III) divisions in 1973. In football only, Division I was further subdivided into Division I-A (the principal football schools) and Division I-AA in 1978. Subsequently the term "Division I-AAA" was added to delineate Division I schools which do not field a football program at all.
The most important differences between Division I-A and Division I-AA are:
Championships
Division I-A football is the only NCAA-sponsored sport without an organized tournament to determine its champion. See Bowl Championship Series for more details on the current system.
Division I-A schools are currently limited to a total of 85 players receiving financial assistance. For competitive reasons, and due to the fact that a student on partial scholarship counts fully against the total of 85, virtually all I-A schools that are not on NCAA probation give 85 full scholarships. The service academies—in this context, Army, Navy, and Air Force—are exempt from this rule, as all of their students receive full scholarships from the federal government.
Division I-AA schools are currently restricted to giving financial assistance amounting to 63 full scholarships. Unlike I-A schools, I-AA schools may give partial scholarships, but are limited to 85 players receiving any sort of athletic financial aid for football. However, competitive forces mean that a substantial number of players in I-AA programs are on full scholarships. Notably, the Ivy League, a Division I-AA conference, does not offer athletic scholarships at all, and a football-only I-AA conference, the Pioneer Football League, also does not offer scholarships. The Metro Atlantic Athletic Conference is another league that sponsors Division I-AA non-scholarship football. Until very recently, the Northeast Conference also sponsored Division I-AA non-scholarship football, but starting in 2006, the NEC will allow a maximum of 30 full scholarship equivalents. Still, the Pioneer Football League, MAAC, and NEC will continue to be classified, at least for now, as Division I-AA "mid-major football" conferences. A national championship team for this level of football is determined annually (since 2001) by a poll conducted by The Sports Network. The #1-ranked Division I-AA mid-major team is awarded The Sports Network Cup on the eve of the overall Division I-AA championship game. (The non-scholarship Ivy League is not part of Division I-AA mid-major football. In fact, the Ivy League operates independently from all other college football conferences. However, its teams are still considered Division I-AA.)