Since we’re stuck in the quagmire of preseason basketball, I thought it’d be fun to put the hypothesis of “it’s just preseason” to the test. Is it really “just” preseason or does anything predictive come from it?
To determine it, I looked at how teams fared in the regular season vs. the preseason over the last five years. Rather than just look at win-loss records, which have less predictive value, I looked at net ratings.
Here are the results:
If you want to get more details, click here to get an interactive version of the chart.
Moving clockwise through the four quadrants, I’ll explain the chart in brief. The teams on the top right prevailed in both the regular and preseasons, the teams in the bottom right only in the regular season, those in the bottom left got trampled in both, and those who are in the top left were preseason pretenders.
You’ll notice the inclining line cutting across the middle of the chart. That’s a trendline, and it indicates that there is, surprisingly, some correlation between winning during the preseason and doing so during the regular season. For stat geeks, the p-value is .00192, so it does have merit to it.
To be fair, though, there are plenty of disparities. However, there are also intriguing tendencies even there.
The 2010-11 Dallas Mavericks, 2013-14 Miami Heat and 2014-15 San Antonio Spurs — all teams who won the title — were all outscored during the preseason. In fact, the Spurs were outscored three of the last five years in exhibition play.
The one thing that all of those teams have in common is that they were teams composed of veteran players who had plenty of experience on the court and a degree of on-court success togehtrer. That indicates that those teams were more likely than not to play their regular starters sparingly in the preseason.
By contrast, some of the teams which showed only preseason success, such as the Minnesota Timberwolves in 2011-12 and again the next year, were teams with young players who were looking to break out. Such teams were playing their regulars more to give them confidence in the upcoming season.
Last season’s Golden State Warriors took their game to a higher level in the preseason and didn’t slow down until…well, they haven’t slowed down yet. The 2011-12 Bulls were one of the best preseason teams and finished tied for the NBA’s best record in the regular season. The 2012-13 Spurs were one of the top preseason teams and also made it to the NBA Finals. So there are plenty of examples of success in both.
So what can we glean from this little exercise? If a team is getting outscored while they’re keeping their starters on the court as much or more than their opponent, it’s unlikely they’re going turn things around once the games start turning around.
If a team is getting outscored but the bench is getting a lot of minutes, it’s probably nothing to worry about, particularly if it’s a group of players who’ve been together for a few years. That’s a team just biding its time until the games count.
And if you’re winning during the preseason? That’s where it gets interesting. If your starters are beating other starters, that probably bodes well, but if your starters are beating up on the end of the other team’s bench, don’t make too much of it.
While net rating tells us something, what may be more meaningful is looking at the comparison by pace:
Here we not only have a trendline which is steeper, but it’s considerably more predictable. There’s a very strong correlation in pace between the preseason and regular season. Ergo, differences in pace that you’re seeing this year in teams like the Chicago Bulls are quite likely to remain the same when the games start counting.
So, preseason might not be overwhelmingly meaningful, but there are things you can look out for to pull what meaning there is out of it.