Does the NBA preseason matter?by Roland Beech, 82games.com
(revised to include 2007-08 season data)
Sure the preseason games matter to the players trying to make the team, the veterans trying to test out their bodies coming from injuries, and for the league itself perhaps to have some build up for the regular season tipoff. The question though is do the preseason records matter?
Is a team's won-lost mark in the exhibition games any indication or tip-off as to how the regular season will unfold? You hear announcers hand down their opinions, but I've yet to see any study on the matter...so let's examine the issue 82games style!
Tracking down preseason stats is no easy feat, but I've compiled a five year database for the 2001-02 season through 2007-08. That's not a huge sample, but a decent look for our purposes.
Now the confidence intervals on these are large due to an n=206, but still it's fair to say that a .35 correlation is reasonably healthy and suggests that yes the preseason records do have some significance in setting a tone for how things may go when the real games begin. The NBA does have more consistency from year to year than many sports, the NFL correlation from one year's record to the next for example was just .25 in one recent five year span.
Also, the fact that an improvement in preseason win % from one year to the next has a .31 correlation to a change in regular season wins is also notable.
BEST preseason records ('01-02 to '07-08)
So that's some pretty nice visual confirmation for preseason believers. Of course it might cross your mind that preseason records could vary in significance based on the prior year success of a team. After all a great team the previous year probably lets the mainstay guys ease through the exhibition games with minimal minutes while the team looking to improve might be running the regular season starters out there for big minutes.
Correlation of Preseason Record to Regular Season Record:
Aha! You say. That proves it then, great teams can ignore the preseason. Well, not entirely, since the sample sizes again get too small to really have conclusive value. Still it is suggestive of that theory, and more importantly perhaps it seems that for a poor prior year team, the preseason results really do have some bearing on whether improvement can be expected.
Teams with winning preseason records off a <30 win season
To put it in perspective, the rare poor prior year team that strings together some wins in the preseason has seen an average gain of 17 wins in the next year!
Now if you extend it to look at any team <50 wins the prior year with a say .700 or better preseason it's a average gain of 7.5 wins.
All right, so which '07-08 teams have shown signs of life in '08-09 "meaningless" games?
6-2 Minnesota (22-60 last yr)
Are we destined to see some revival for the Timberwolves this coming season? Trying to project performance from the preseason alone is likely a foolish endeavor, but on the other hand if you're a fan of a team that's anything less than a rock solid 50+ win type, you might want to root for some exhibition wins after all.
One last oddity to wrap it up: teams that have improved their preseason win% over last year by .400 or more gain an average of 17 wins...this season that again tabs the Timberwolves, but also the Hornets who were .500 in '07-08 preseason but a perfect 1.000 this time out!
On the flip side, teams that lose .250 or more off their preseason win% have lost an average of almost six wins...this season Charlotte, Milwaukee, Sacramento, Memphis, Indiana, Toronto and Atlanta "could have done better" in the October classics.
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