ABSTRACT: both major leagues
have adopted radically unbalanced schedules for the 2001 season, in which
teams will play
up to 20 games against divisional
opponents, but as few as 6 against most non-division league opponents.
This paper shows
that these unbalanced schedules
are likely to create new headaches for analysts trying to adjust raw performance
for context.
Because teams' road schedules overrepresent
stadiums within one's own division, conventional measures of park effects
are
likely to be misleading, especially
if some divisions have better hitters parks than others. Meanwhile,
unbalanced schedules will
also create inequities in the quality
of competition faced by players on different teams; Baltimore hitters,
for instance, will have to
face the Yankee and Red Sox pitching
staffs 19 times each in 2001, while getting to face Ranger pitching only
6 times. The
main paper discusses the problem
at an intuitive level and shows that the gaps between conventional estimates
and reality may be
quite large in 2001 and beyond.
The technical appendix derives a new method for computing park factors
and other performance
adjustments that is valid under
unbalanced schedules. The supplemental table presents results from
applying my method to
unbalanced schedule seasons in
both leagues since 1969.