NBANBA

Think Fast: NBA Teams Don’t Stay Good for Long

That slow, meticulous rebuild won’t lead to a title window as long as you think. We dive deep into how quickly things change in the NBA, no matter how good you are in the present.

By Zach KramJune 27, 2019, 10:20 am UTC • 7 min

It seems as if thinking about the NBA involves more long-term prognosticating than ever. Free agency for stars begins two years in advance. Trade scenarios are cooked up as soon as someone signs. Early mock drafts come earlier each year. But are our assumptions about the future of the league’s best and worst teams ever accurate?

We looked at all teams since 1988-89, the first season with unrestricted free agency, to see how precisely we can pinpoint a team’s future based on its present. The answer? The current NBA landscape predicts the future NBA landscape about as well as Shaquille O’Neal’s MVP season predicted Steph Curry’s.

Let’s start with the basics. We find that a team’s record in a given year (Year X) can explain 44 percent of its record one year later (Year X+1)—56 percent can be attributed to other factors. That’s a fair portion, and it far exceeds the predictiveness in other sports. An MLB team’s record explains just 22 percent of its next-year record, and the NFL is at 11 percent.

But for anything further than one year in the future, a team’s current quality is virtually meaningless. By the third year (Year X+3), a team’s current record can explain just 7 percent of the future; by the fifth year (Year X+5), that’s a measly 1 percent.

The NBA standings are therefore elastic, meaning they easily change shape over time, and that discovery carries a number of implications for both teams and analysts. For instance, it can explain, in part, why unprotected draft picks traded far in advance often don’t yield the kind of premium selections that teams might hope. Just because, say, the Kings were one of the league’s worst teams when they traded their 2019 first-rounder in 2015 doesn’t mean that they’d still be one of the league’s worst teams by the time the pick conveyed; in fact, that pick ended up 14th overall.

Similarly, it’s easy to dream on this Bucks team, which enjoyed a historically great 2018-19 regular season and features the league’s newest MVP in Giannis Antetokounmpo. But even their future is less certain than those facts would suggest: A slew of crucial contributors—Khris Middleton, Brook Lopez, Malcolm Brogdon, Nikola Mirotic—are free agents this summer (Brogdon is restricted), so Mike Budenholzer’s roster could look markedly different next season, or else capped out and unable to make meaningful additions going forward. It’s possible the Bucks’ championship plans will dissipate as quickly as they appeared.

To investigate further, we took a closer look at how well present-day success predicts success over the next five seasons. We split teams into three broad categories: “Good” teams win 50 or more games in a season (or the winning-percentage equivalent in a lockout year), “bad” teams win 30 or fewer games, and “decent” teams are the mass between. What happens in the next handful of seasons for the teams in each grouping?

Good Teams

Good teams don’t stay good for all that long—not even the full length of a star’s prime. This chart shows the percentage of good teams that stayed good or fell to decent or bad after a certain number of years.

About two-thirds of good teams stay good the following year, which is encouraging, but only about half are still good two years later. By four and five years later, only about a third are still good. And that four-and-five-year total includes a number of teams who were good, struggled, and then rebounded, so their championship window wasn’t open that entire time. Overall, only 16 percent of good teams, or one in six, maintain their current quality for each of the next five seasons.

How do those lessons apply to 2018-19’s good teams? Using the 50-win marker, eight teams qualify: the Bucks, Raptors, Warriors, Nuggets, Rockets, Trail Blazers, 76ers, and Jazz. Within two seasons, we’d expect four of those teams to no longer be good; over the next five seasons, we’d expect just one or two of those teams to stay good the whole time. Even the most carefully crafted long-term team-building plans go awry much more often than not.

But to their credit, those good teams are also unlikely to collapse immediately. Just six teams have fallen from good to bad—skipping over decent—in the span of a single offseason:

• The 1993-94 to 1994-95 Warriors, who traded Chris Webber and lost Chris Mullin to injury 
• The ’96 to ’97 Spurs, who lost David Robinson for the season and tanked for Tim Duncan
• The ’98 to ’99 Bulls, who lost Michael Jordan, Scottie Pippen, and Phil Jackson
• The ’99 to ’00 Hawks, who faded in Lenny Wilkens’s final season as their coach
• The ’10 to ’11 Cavaliers, who lost LeBron James
• The ’18 to ’19 Cavaliers, who lost James again

Decent Teams

Here’s that same kind of chart for teams that are decent—between 30 and 50 wins—in a given season.

Decent teams tend to stay decent over time—but that’s not much of a revelation, because teams of all stripes trend toward the middle. That’s simple regression to the mean. The more interesting takeaway here is that teams already in the middle are equally as likely to move up in the NBA’s hierarchy as they are to move down.

Basketball has the least parity of any major U.S. sport, and the NBA has a perception that it’s exceedingly difficult to break into the upper crust. Compared with the league’s own past, however, the last decade has seen healthy competition between a wider swath of teams. From 1980 through 2009, eight franchises combined to win 30 titles. In the 2010s alone, seven teams have won, and 26 of 30 teams have won at least one playoff series. (Apologies to Charlotte, Detroit, Minnesota, and Sacramento.)

There’s still a fair likelihood that a decent team will become stuck in middling purgatory—not good enough to contend for a title, not bad enough to start a contention cycle anew. But as these results show, teams in the middle aren’t doomed to this fate, either: About half escape within a couple of years, and both directions—up or down—represent a viable alternative.

Bad Teams

And finally, here’s the precedent for bad teams’ future outlook.

It looks like the good teams’ chart in reverse. The majority of bad teams stay bad the next season, but within two seasons, more have ascended to decent or good than remained bad; within five seasons, they’re scattered across the spectrum. Look at that X+5 column. It’s not that different from the X+5 column for the good teams—which is just another way of saying that from five years out, there’s not much separation between a team that’s currently near the top of the league and a team that’s currently at the bottom. Their futures look surprisingly similar through a wide-angle lens.

That doesn’t mean it’s easy for bad teams to break through to the top. Merely 35 percent of bad teams enjoy a 50-win campaign at any point in the next five seasons. So even if bad teams escape from the bottom, they’re unlikely to ascend higher than the middle. From New York to Orlando to Sacramento to Phoenix, the league is full of situations that have seemed hopeless at one point or another this decade.

But five years is a long time, and the NBA also has mechanisms in place to boost parity. The draft, most obviously, allows the worst teams to add the best new players. The salary cap effectively prevents the best teams from retaining their cores year after year. And with shorter contracts and accelerated player movement, there may yet be greater year-to-year fluctuations in team performance. Indeed, splitting the predictiveness results by decade shows that the 2010s saw much starker changes in team performance than the 1980s and 1990s.

So a bad team isn’t necessarily trapped into its situation any more than a good team is destined to remain good for seasons to come. Poor ownership and management might prove incredible hindrances to team improvement—and indeed, some teams do remain trapped at the bottom for a half-decade or more—but future NBA performance looks kind of random from a present-day perspective. 

Statistically, we know basically nothing about which teams will be the league’s best and worst just three years from now. That conclusion fits with what we’re seeing now, too. The Lakers could be a title contender with James and Anthony Davis, or they could struggle with a post-prime LeBron. The Warriors might rely on two 30-something guards. The Bucks will have had to contend with Antetokounmpo’s free agency. Kawhi Leonard might be anywhere. The Kings and Timberwolves might have young stars just rounding into form. And the league’s standings will continue to spin and shift like Curry turning around a screen at the top of the key.

Zach Kram

Zach writes about basketball, baseball, and assorted pop culture topics.