Posted by Neil Paine on October 29, 2008
BBR is pleased to announce that Neil Paine will be blogging for us throughout the 2008-09 season. Neil is a frequent contributor on the APBRmetrics message board as well as ArmchairGM. We think Neil is a great addition to the site and we look forward to working with him this season. —JK
We've all heard the cliché: "On opening night, every team is tied for first place." And there's no denying that the start of a new season brings a certain measure of optimism to even the most long-suffering of NBA fans. "This could be the year," they say as they look at their team's roster. "Why not?" They can even point to Boston's 2007-08 turnaround as evidence that a few key off-season trades can turn a team from a bottom-feeder into a champion overnight.
But then they have to actually play the games.
After one game, every team is obviously either 1-0 or 0-1; exactly 1.2% of the season has been completed. And while it's pretty early to be ordering (or canceling) those playoff tickets just yet, opening night has to tell us something about each team, right? Well, here are some fun factoids about success on opening night leading to bigger things...
- Since the NBA/BAA began play in 1947, 61.8% of eventual playoff teams have won their first game of the season. In the decade of the 2000s, though, that number is just 59.7%.
- In 2004-05, eventual playoff teams went just 8-8 on opening night. In 2006-07, more of them actually lost than won their first game (they went 7-9). So, yes, there's hope for a postseason berth even if your favorite team drops game #1 of the year.
- Last year, though, 12 of the 16 playoff teams won their first game, which was the best mark in the league since the 1996-97 season.
- In 1946-47, all 6 BAA playoff teams won their first game. In NBA history, the best cumulative opening-game winning percentage for playoff teams is .875, which has happened 3 times (the last time coming in 1973).
- Since the league expanded the playoffs to 16 teams in 1983-84, the largest number of opening-game wins by eventual playoff teams is 12 — and it's happened only twice.
- Eventual NBA champions have gone 47-15 on opening night, for a winning percentage of 75.8%. The last champs to drop their first game were the 2003-04 Detroit Pistons, who lost 89-87 to the Indiana Pacers on October 29, 2003.
- Starting the season at home doesn't really help a team over the course of the season (I know, big surprise): in NBA history, teams that opened at home could expect to win 0.04 more games per season than their road-opening counterparts. Now, this is a real advantage — the odds of this occurring due to random chance are basically nonexistent — but it's such a small advantage that it's essentially meaningless.
- Point differential on opening night doesn't tell us a whole lot about a team's quality, either: in NBA history, the correlation between a team's opening-night margin of victory/loss and its average margin for the season is just 0.38.
- Even so, being on the receiving end of an opening-night beatdown probably doesn't bode well for your season. 11 NBA teams have lost by 33 or more points on opening night, and only one of them (the 1973-74 Capital Bullets) finished in the top half of their league in SRS. Four ended the season as the NBA's worst team by SRS, and two more finished as either the second- or third-worst team in the league.
So, in the end, how much does opening night actually matter? Well, eventual playoff teams tend to win their first game about 60% of the time... but playoff teams tend to win that percentage of their games anyway, opening night or not. The same goes for championship-caliber teams — they win game #1 a lot, but they also do well in games #2-82. The fact that there's a relatively weak correlation between opening-night margin of victory/loss and end-of-season average point differential just drives this point home: no matter what happens this week, it's not necessarily a sign of things to come, good or bad.
That said, if your favorite team ends up losing by 30+ points this week, you may in fact be in for a long season. Just warning you ahead of time.