What the Rockets' historic turnaround portends for their future

The Houston Rockets were quietly one of the best stories of the 2023-24 season. The injection of a new coach, Ime Udoka, and sturdy veterans, Fred VanVleet and Dillon Brooks, to a promising young core, saw the team shoot up the standings and left their three-season run at the bottom of the league in the dust. While awards voters took notice of the improvement with Alperen Sengun finishing third in Most Improve Player voting and Udoka finishing seventh in Coach of the Year voting, the magnitude of their turnaround was gravely overlooked.  

The 2023-24 Rockets were historic 

The 2023-24 Rockets orchestrated one of the best turnarounds in NBA history. Their 19 win improvement was the 61st largest season-to-season improvement in NBA history and their 0.232 boost in win percentage ranks 51st. In a sample of nearly 1,600 individual team seasons, ranking in the top 100 is incredibly impressive, but even their raw win improvement sells them a bit short. 

The Rockets’ 8.86 season-to-season improvement in Simple Rating System (SRS), the sum of a team’s per-game margin of victory and strength of schedule, was the 19th greatest, and their 9.0 improvement in net rating was 24th. In both descriptive and predictive statistics, the Rockets executed one of the greatest 180-degree turns in NBA history, but I still wanted to know exactly where it ranked all-time. 

Where the 2023-24 Rockets turnaround ranks all-time

To determine where the Rockets’ 2023-24 season improvement ranks all time, I took every eligible season (only seasons from current NBA franchises, no ABA seasons, and excluded a franchise’s first season in the NBA/BAA) and averaged their rank across total win, win percentage, SRS, and net rating improvement from the previous season. Based upon this admittedly simple ranking solution, the 2023-24 Houston Rockets engineered the 33rd greatest single-season turnaround in NBA/BAA history. 

While calling a .500 team historic seems a bit much, any way you slice it, their turnaround was in rarified air. However, while the 2023-24 season was a resounding success, it’s also over. The much more important question is what does their staggering improvement tell us about their chances next season?

The plexiglass principle 

Bill James, the father of modern sports analytics, coined the plexiglass principle while writing his annual Baseball Abstracts in the 1980s. It’s the most basic of analysis, but the general premise is teams that improve in one season decline the next, and vice versa, and this is especially true of teams that take massive leaps. The principle is functionally just regression to the mean, but James’ abstracts included five other indicators for future success, four of which have value to basketball. 

Pythagorean record: A team’s expected win-loss record based on point differential. SRS and net rating are functionally the same as point differential. 

The law of competitive balance: Teams tend to return toward a .500 record. This is similar to the plexiglass principle.

Age: Young teams, in general, tend to improve, while old teams, tend to get worse. 

Late season performance: Teams that play better in the second half of the season compared to the first half tend to improve the next season. This marker is likely less indicative in the NBA than in the MLB. In the NBA, young impact players aren’t in the minors only to be called up in the second half of the season, and depending on your schedule, you may face a string of teams actively trying to lose. 

Based on the plexiglass principle, the 2024-25 Rockets should see their record drop from 41-41. However, they have a few interesting markers that make continued improvement more likely, although far less dramatic than what they accomplished in 2023-24. 

What similar teams to the 2023-24 Rockets tell us about 2024-25

To get a better idea of what teams that improved to the degree the Rockets did in 2023-24 did in their follow-up season, I took the teams ranked 15th through 50th in my simple ranking solution, excluding the 2023-24 Rockets, and found what they did in the season after their jump. This cohort of teams, on average, improved by plus-20.5 wins, plus-.251 in win percentage, plus-7.8 in SRS, and plus-8.3 in net rating in their jump season, but saw their win total and win percentage decline by minus-0.7 and minus-.006 in the following season. However, their SRS and net rating did improve marginally by plus-0.16 and plus-0.11.

These results over the larger sample are unsurprising. Teams that make a sizeable leap are usually about as good the next season, but that doesn’t doom the Rockets to another mile on the mediocre treadmill. The average leap season saw a team win 47.6 games at a .590 win percentage with a 2.7 SRS and net rating of plus-2.9. The 2023-24 Rockets were well below those figures, and the larger sample includes many teams that made a jump into the 50-win territory.  

Narrowing the field down further, I took teams that won between .450 and .550 percent of their games, and/or had a simple rating or net rating between 1.15 and 1.30 in their leap season. This new group of 13 teams all experience similar leaps to a familiar place as the 2023-24 Rockets, and thus makes their follow-up season more indicative of what we can expect from the 2024-25 Rockets. 

On average, this group won three more games (44), improved their win percentage by 0.039, their SRS by 1.2, and their net rating by 1.1. While that level of improvement wouldn’t vault the Rockets into a playoff lock, it’s more inspiring than the larger sample holding serve. 

What to expect from the Rockets in 2024-25

Should you pencil the 2024-25 Rockets in for 44 wins? Probably not. There’s a whole offseason ahead of us, and the Rockets have so many young players that a more sizable jump isn’t out of the question. Many of the teams that experienced a second jump either added a star player (2020-21 Suns, Chris Paul) or had a young superstar on the roster who made the leap (1993-94 Magic, Shaquille O’Neal). Both options remain viable for the Rockets considering their depth of young talent and draft assets, but barring that, a 50-win season looks unlikely.  

However, while the ceiling for the 2024-25 Rockets remains in flux, their floor seems very secure. Outside of catastrophic injuries up and down the roster, the Rockets should be around .500 at worst, which is a nice reprieve from their three-season 20-wins and a top-five pick tour from 2020 to 2023. 

The Rockets rebuild is on extremely solid footing, and their 2023-24 season should be celebrated for the achievement it was. Out of 1,597 seasons, it was the 33rd greatest season-over-season improvement, putting it nearly into the 98th percentile. While another jump of that magnitude is unlikely, it isn’t out of the realm of possibility. Even if 2024-25 isn’t the season the Rockets break back into the playoffs, it looks like it is only a matter of time.