 For most situations, simply squaring each variable yields accurate results.There are some systematic statistical deviations between actual winning percentage and expected winning percentage, which include bullpen quality and luck.In addition, the formula tends to regress toward the mean, as teams that win a lot of games tend to be underrepresented by the formula (meaning they "should" have won fewer games), and teams that lose a lot of games tend to be overrepresented (they "should" have won more).