Sports leagues consist of conferences subdivided into divisions. Teams play a
number of games within their divisions and fewer games against teams in
different divisions and conferences. Usually, a league structure remains stable
from one season to the next. However, structures change when growth or
contraction occurs, and realignment of the four major professional sports
leagues in North America has occurred more than twenty-five times since 1967.
In this paper, we describe a method for realigning sports leagues that is
flexible, adaptive, and that enables construction of schedules that minimize
travel while satisfying other criteria. We do not build schedules; we develop
league structures which support the subsequent construction of efficient
schedules. Our initial focus is the NHL, which has an urgent need for
realignment following the recent move of the Atlanta Thrashers to Winnipeg, but
our methods can be adapted to virtually any situation. We examine a variety of
scenarios for the NHL, and apply our methods to the NBA, MLB, and NFL. We find
the biggest improvements for MLB and the NFL, where adopting the best solutions
would reduce league travel by about 20%.Comment: 20 figures, 1 tabl