Rankings and Strength of Schedule

Every week during the football season various polls are released ranking the best teams.  The term best, meanwhile, is a vague, intangible superlative.  Sometimes the rankings reflect who would likely win if the teams were pitted against one another, and sometimes the rankings reflect consensus of which teams are more deserving of opportunity and prestige.  Whatever the case may be, all subective rankings appear to be a function of pre-season assumtions and wins and losses, rather than a fresh ranking each week.  Thus, losing teams almost always drop, but non-losing teams often move up only when teams ahead of them lose.

This relationship brings about an assortment of odd instances.  For instance, a team may win one week and drop a few spots in the polls only to move up even more spots the next week despite having a bye.  Other times, a slightly lower-ranked team can defeat a slightly higher-ranked team, yet remain ranked lower when the new polls are released.  Furthermore, because teams with greater notoriety are more likely to begin the year ranked highly in the polls, a bias exists favoring such teams.  Such inconsistencies call into question the worth of polls.

Strength of Schedule (SOS) is typically a calculated measure of the average difficulty of a team’s scheduled games.  For several important reasons, these measures must be taken with a grain of salt.  First, SOS is based on teams’ rankings, which are influenced by SOS ratings.  This circular logic, while it can be objectively automated, ultimately must be based on a beginning rating, which almost inevitably introduces and entrenches bias in the measure.  Second, any given teams’ rating will fall after losing, so by winning a team effectively lowers its SOS rating.  While this is true for all winning teams, the degree of change may not be the same for all teams.  Because teams unfavored by the inherent bias generally play more teams also unfavored by the bias, there is reason to speculate that the negative effect on an opponents SOS is greater in magnitude for already unfavored teams.  Third, SOS implicitly ignores the ups and downs teams naturally experience, and cannot accommodate the fact that teams match up differently against some than others.  Fourth, SOS factors in the average difficulty of all games, and thus creates bias against teams in conferences perceived as weak.  It’s true that it is more difficult to play tough teams week in and week out, so playing a single good team may not reliably serve as a litmus test of a team’s strength; however, it can be argued that a team playing a few good teams and a few more poor teams has a tougher road than a team that plays a straight set of average teams.  Because of this fact, no matter how many top teams a non-AQ team schedules in non-conference play it will be at a perhaps unjustifiable disadvantage because of SOS ratings.