If you’re an NBA fan, you’ve probably run across “worst-ever” headlines about the Eastern Conference teams, which include such fabled franchises as the reigning champ Miami Heat, Boston Celtics, and Chicago Bulls. This group really is bad enough to warrant all that abuse.
Through Sunday night’s games, teams in the Western Conference had a combined record of 169-133, while the East had an aggregate record of 133-169. That gives the East a total winning percentage of 44 percent in all NBA games this year:
However, most games are played within conference. The East is 102-102 against itself this year, and the West is also 102-102 against itself. The entire difference comes from the West’s 67-31 record in games played against the hapless East. In out-of-conference games, the West has a huge 68 percent to 32 percent winning margin. (Hey, things are looking up for the East, whose tally stood at 29 percent last week!)
Make no mistake: The East’s measly success rate against the West is not much of a surprise. It has been losing to the West for the past decade. (The NBA Finals have been more even: five wins apiece per conference in the last 10 years.)
With bizarre consistency, Eastern teams beat the East in 42 percent of games in the past three years. (Yes, each year was exactly 42 percent.) The average over the past decade has been 43 percent. Such stability highlights Eastern weakness as a fact of life.
The strange thing is how consistent the process has been. Even a large factor such as the draft, in which the worst teams hold the advantage, hasn’t been enough to shift this relationship.
Assuming that 43 percent is the “true” rate of Eastern weakness, does this year’s 32 percent rate suggest a statistically significant change in the strength of the conferences. According to the binomial distribution, there is less than a 10 percent chance that the East could be this bad merely by random chance.
That means the winning-percentage drop probably constitutes a real change in the conference’s stature. For the most part, it won’t matter. Out of an 82-game schedule, only 30 games are played out of conference:
With 52 games played in-conference, the average number of wins is a minimum of 26 for the conference. Even if the East lost every single game against the West, its teams would still average 26 wins, simply from playing each other. On the flip side, if the West were to win every single game against the East, its teams would average 56 wins for the full season.
At the current 32n percent rate, we are on pace to see the East’s teams average a 36-46 record, while the West would average 46-36.
Even the upcoming “epic” draft class of 2014 might still fail to meaningfully affect the East’s losing streak.