Retrospective Strength of Schedule in the NBA

Not every NBA schedule is created equal. Some teams face killers all season; others cruise through a soft draw. We call this difference schedule luck — and it’s measurable.

The idea: instead of the usual strength-of-schedule metric (opponents’ combined winning percentage), use Elo ratings — a more precise measure of team strength that updates after every game. Then look backwards: not “how hard is the remaining schedule?” but “how hard was the schedule you actually played?”

Data: Every NBA game since the 1976–77 merger through 2024–25, sourced from Neil Paine’s Elo database (successor to FiveThirtyEight’s model). A team’s luck score is the z-scored average opponent Elo within its conference — positive means an easier draw than peers, negative means a tougher one.

East vs. West

The biggest driver of schedule luck is conference strength. If your conference is weaker, you play more games against weaker opponents. The chart below shows how the average opponent Elo has shifted between conferences over nearly five decades.

In the 1980s the East was actually tougher — by about 12 Elo points. That gap reversed through the 2000s, and the West has been clearly harder since 2010. The magnitude is small in absolute terms (roughly the difference between a 6th and 8th seed) but it compounds across an 82-game season.

When Teams Transform Mid-Season

Schedule luck also comes from when you face an opponent. A team that collapses mid-season gives early opponents a tough game and late opponents an easy one. The four most extreme single-season Elo swings in NBA history:

Each has a clear story: Chicago cratering after Jordan’s second retirement (1999), Cleveland imploding after LeBron’s Decision (2011), Boston surging after adding the Big Three (2008), and San Antonio deliberately tanking in 1997 — dropping from 1585 to 1275 Elo — only to draft Tim Duncan and rocket back up in 1998. Teams who faced these squads before the transformation had a very different experience from those who faced them after.

2012 East: The Extreme Case

The lockout-shortened 2011–12 season produced the starkest luck gap in the dataset. Miami and Chicago were the East’s two best teams — separated by just 8 Elo points in team strength. But their schedules diverged wildly: Chicago’s average opponent Elo was 1481, Miami’s was 1504. A 23-point gap, all down to scheduling.

Chicago got the lucky draw, Miami the unlucky one. Both led the conference in wins, but Chicago’s first seed came against measurably weaker opposition. Miami, for their part, went on to win the championship.

The Record Book

A few stand-out seasons from nearly five decades of data:

• Hardest regular season: The 2020 Pelicans faced an average opponent Elo of 1533 — the toughest draw since the merger. They missed the playoffs.
• Luckiest regular season: The 2003 Pelicans (then Hornets) had the softest schedule relative to their conference peers — went 47–35 and lost in the first round.
• Hardest playoff gauntlet: The 2010 Celtics — as a 4-seed they swept D-Wade’s Heat, battled LeBron’s Cavs, fought peak Dwight Howard’s Magic, and finally fell to Kobe’s Lakers. Average playoff opponent Elo: 1684.
• Smoothest championship run: Magic Johnson’s 1987 Lakers cruised through 18 games against opponents averaging just 1552 Elo.

Explore the Data

Filter by era, conference, or team. Click any point to see details in the table.