“The triple-double is just a stat. It’s a test of your strength and stamina and playing ability, really.”
– Oscar Robertson
I would probably also include that a triple-double is a testament to a player’s versatility, but I’ll happily defer to Mr. Robertson on this one. In 1962, Oscar Robertson averaged 12.5 rebounds, 11.4 assists, and 30.8 points per game to become the first NBA player to average a triple-double (double digits in three of five major statistical categories). And he was the only player to ever do so until Russell Westbrook finished the current season averaging 10.7 rebounds, 10.4 assists, and 31.6 points per game. Westbrook also bested Robertson’s record for most triple-doubles in a season with 42 triple-doubles in his 81 games played.
If you followed the NBA this regular season, you probably noticed that players seemed to rack up triple-doubles at a much higher rate than usual. Westbrook gets the majority of the attention (as I think he should!), but plenty other players were in on the action too (James Harden, LeBron James, and Nikola Jokic to name just a few). The boom in triple-doubles got me wondering if I could find any interesting data related to the subject. Luckily my go-to site for finding basketball data, basketball-reference.com, provides a convenient summary of every triple-double back through the 1983-1984 season. After a quick call to the Internet Open feature in JMP, I had all of the data in JMP and ready to go. Perfect!
A First Look at the Data
With more than 30 years of data ready, the first thing that comes to mind is to plot the number of triple-doubles per season.
Just as we were expecting, there is a huge jump in the number of triple-doubles this season. But not so fast! Not every season is created equally, so looking at these raw counts could be very misleading. Until the 1987 season, there were only 23 teams in the league as opposed to the current 30 team lineup. And some seasons were cut short by strike, as in 1999 when teams played a 50-game season instead of the usual 82. In order to make a fair comparison, we should be looking at the triple-double rate for each season. Instead of the raw counts, we can use the number of triple-doubles per 100 games:
Adjusting for Pace of Play
But there is still some room for improvement in the analysis. The 1980s were known for having a high pace of play (think Magic Johnson and the Showtime Lakers), whereas the 1990s brought a slower grinding style. Higher pace means more shots, more points, more rebounds – and as a result, more opportunities to score a triple-double. So it may be that players from a different era are more or less likely to score triple-doubles because of pace of play. Fortunately, basketball-reference also provides a measure of pace for each season: the average number of possessions per game. Adjusting for pace allows us to more easily compare players across eras. I can think of a handful of ways to adjust for pace, but I went with a simple one:
Now we get a much more honest picture of how triple-doubles have changed over time. This season was still a break-out year, but it is not as dramatic as the first graph led us to believe.
This season, we also saw records set for the most points in a triple-double as well as the fewest points in a triple-double. Those honors belong to Russell Westbrook and Draymond Green, respectively.
In fact, Draymond Green became the first player to ever record a triple-double without scoring double-digit points. Some players are able to have a huge impact on a game even without scoring many points and Green’s game here is about as good of an example of this point as you will find. I think that this is one of the things that makes the accomplishment so interesting: There are so many different ways that it can be done. This got me wondering: Of the 1,500+ triple-doubles in the data set, can we find any truly unique cases that stand out from the rest?
Finding the Principal Components
There is no shortage of ways that I could look for games that stood out from the pack. Since I have 1,500+ observations and about 15 columns (field goal attempts, points, rebounds, turnovers, and so on), my first thought is to look at the Principal Component Analysis. When I look at a plot of the first two principal components, I’ve labeled two points that seemed to jump out from the rest. We could certainly make the case for other points, but these were the two that stood out to me: a 1987 game from Hakeem Olajuwon and James Harden’s gem from this past New Year’s Eve.
These two performances have to make any Houston Rockets fan proud! In my opinion, these are two of the better individual performances of all time. Olajuwon came painfully close to a quintuple-double, just a couple of assists and steals shy. Olajuwon later went on to become one of only four players in NBA history to notch a quadruple-double (points, rebounds, assists, and blocks) in 1990.
The graph of the first two principal components provides a nice visualization of how different players get their triple doubles. The bottom of the point mass is where you tend to find good defensive centers who can rack up 10+ blocked shots (for example, Dikembe Mutombo, Shaq, and David Robinson). The right side of the point mass tends to be guards who score a lot of points and take a lot of free throws, players like James Harden and Russell Westbrook. And the top of the point mass tends to be the strongest three-point shooters like Steph Curry. Of course, we also have versatile players like Magic Johnson, Larry Bird, and LeBron James who are scattered all over the plot.
Answering the Big Question
The 2016-2017 NBA regular season was like no other, and the playoffs (which started over the weekend) are unlikely to disappoint. In particular, I’d be amazed if the first round series between the Oklahoma City Thunder and the Houston Rockets didn’t provide us with at least a few more triple-doubles.
Now for the big question: Why are we seeing such a spike in triple-doubles? I suspect that two things have contributed greatly to the triple-double boom: the increased pace of play and the prevalence of the three-point shot. As we’ve already discussed, a higher pace means more possessions and more opportunities to score, assist, and so on.
And this season was also a record year for three-point attempts, teams are taking more threes than ever before. Why are threes important in fueling triple-doubles? For one, made three-point attempts usually result in an assist. Long range shooters tend to like to catch the ball and shoot immediately, so whoever passed them the ball gets an assist on made shots. This bumps up the number of assists per game. And another reason is that long shots usually have long rebounds. So a missed three-point attempt is more likely to bounce back out to the perimeter where guards can boost their rebound numbers. In times where players took fewer threes and more short shots, guards would have a harder time collecting rebounds in the paint among the much bigger forwards and centers. That’s just one idea.
Feel free to add a comment with your opinions. Enjoy the playoffs, and let’s go Hawks!