Strength of schedule means little

Chris Paul, Avery BradleyGreg M. Cooper/USA TODAY Sports

There's a famous story, probably apocryphal, about Larry Bird examining his team's schedule for the upcoming NBA season.

"Forty-one home, 41 away," Bird concluded. "Yup, looks right to me."

Even if the tone is flippant for effect, the message isn't far off. Unlike the NFL, where the schedule can make or break a team's season, in the NBA it has little to do with overall performance.

Within conferences, teams' schedules differ by just four games each. They play all four division rivals four times, two home and two away, and the same number against six of the 10 teams in other divisions in the same conference. Which four teams that play just three teams rotate randomly over a five-year cycle.

That leaves three factors that have a consistent, significant impact on each team's strength of schedule: conference, team ability and back-to-back games. Let's take a look at these three factors:

1. Conference

More than anything else, the quality of the conference in which a team plays determines the strength of its schedule. That's been particularly true because of the large gap between the stronger Western Conference and the weaker Eastern Conference dating back nearly a decade and a half.

Last year, the West won 63.1 percent of matchups between the two conferences, the second-highest mark since the NBA-ABA merger. So naturally, West teams had it more difficult schedule-wise than their East rivals. In fact, to demonstrate the importance of conference-to-schedule strength, every single Western Conference team played a tougher slate of opponents than every single Eastern Conference team.

2. The team's own ability

Alert the conspiracy theorists: Besides conference, the other factor that plays a large role in determining a team's strength of schedule is how good the team is. Last season, the hardest schedules in terms of opposition were played by the West's three worst teams: the Los Angeles Lakers (+0.92 points per game harder than average),  Utah Jazz (+0.86) and Sacramento Kings (+0.78). Meanwhile, the three easiest schedules belonged to teams near the top of the East standings: the Washington Wizards (-0.75),  Indiana Pacers (-0.73) and Toronto Raptors (-0.65).

Before you start complaining again about the NBA favoring the league's best teams, understand that this is a function of an obvious problem: Teams can't play themselves. So the worst teams in the conference play a higher percentage of their games against the best teams, and vice versa.

This factor isn't always more important than which conference opponents play three teams instead of four -- witness the East's No. 2 seed, the Miami Heat, playing the conference's fifth-hardest schedule last season. But within a conference, about 70 percent of the variation in a team's strength of schedule is determined by its own record.

3. Back-to-backs

The one thing Bird should have been checking for on his schedule was back-to-back games, and more generally the kind of rest the team would get. Based on recent research by Jeremias Engelmann on the APBRmetrics forum, teams are about 1.5 points per game worse in the second game of a back-to-back, and lose an additional point when playing for the fourth time in five nights. That, more than opponents, is where the league can have an effect on a team's schedule.

And there can be big differences among teams in terms of back-to-backs. Last season, the Denver Nuggets played just 14 back-to-backs as compared to 22 for the Atlanta Hawks and Milwaukee Bucks. While that meant more long breaks for the Hawks and Bucks, Engelmann found that teams actually perform marginally worse with multiple days off than on one day's rest, so things don't even out.

Still, over the course of an 82-game schedule, this effect is relatively small. The difference between the league's easiest schedule in terms of rest (the Golden State Warriors, who played 15 back-to-backs) and the hardest (Bird's Indiana Pacers, with 20 back-to-backs and three times with four games in five nights) averaged 0.22 points per game -- less than a quarter the schedule difference attributable to conference imbalance.

As much fun as it is to check out the newly-released NBA schedule and highlight important matchups for the 2014-15 season, ultimately the schedule doesn't make a lot of difference to teams' bottom-line results. Those won't be determined until the season starts in late October.