Visualizing the Evolution of the San Antonio Spurs with Tableau
Peter Xing, Former Viget
With their Game 5 victory over the Miami Heat this past month, the San Antonio Spurs officially won their fifth championship in the Tim Duncan and Gregg Popovich era, dating back to the 1997-98 season. Recently, much has been made of the Spurs’ consistency since Duncan entered the league: 17 consecutive trips to the playoffs, and regular season win percentages above 60% for each of those seasons.
Basketball experts and fans alike have observed that the Spurs have evolved from being a defensive juggernaut to an offensive powerhouse. I wanted to see if the data supported the NBA eye-test. Analyzing stats from basketball-reference.com with Tableau Public--just released for Mac--this is what I found.
A Quicker Offense
The Spurs offense has seen a notable uptick in pace, or possessions per 48 minutes, over the last few years. Early in Duncan’s career, the Spurs were a grind-it-out team that punished opponents deep in the paint through both David Robinson and Duncan. As Duncan has aged, however, the offense has transitioned into a more balanced attack, using multiple screens and floor spacing to generate a quicker offense and field goal attempts earlier in the 24-second shot clock. This strategy has led to an increase in the number of possessions per 48 minutes, from 88.4 in Duncan’s rookie year to a Duncan-Popovich Era high of 95.0 this past season--good for 10th in the league, despite the Spurs fielding the fourth oldest roster.
One would expect that more possessions and a quicker pace would lead to more field goal attempts, and indeed that is the case. Not only have the Spurs turned out a higher number of attempts over the last few seasons, but more attempts have come from the three-point range. Teams throughout the league have incorporated the 3-point shot into their offense more heavily over the last decade, and the Spurs are no different. Since winning the 1999 NBA championship with only 10.8 3-point attempts per game, good for 24th in the league, the Spurs have steadily increased their attempts to 21.4 attempts per game in the 2013-2014 season. Additionally, they have been above the league average fairly consistently in both attempts and 3-point field goals made over the last eight seasons. From the data, it seems that most of the increase in FG attempts over the last 17 years has come in the form of 3-point attempts.
Amazing Offense, but still Strong Defense
In the 1998-99 regular season, the Spurs were the most dominant defensive team in the league, allowing 95.0 points per 100 possessions, more than two points fewer than the second-best defensive team. And, in the following three championship years (2002-03, 2004-05, 2006-07), the Spurs maintained a defense that ranked in the top 3. Despite a steady decrease in the Spurs’ defensive rating throughout the years, this decrease seems to be more indicative of the league’s overall transition to a faster pace and more offensive style of play.
Watching the NBA playoffs this year, much of the focus was on the Spurs' offense and how it continually broke down defenses with ball movement, multiple pick-and-rolls, and great shot selection. And, after the mindboggling shooting displays that the Spurs dropped on the Heat and their vaunted trap defense (59.4% and 57.1% shooting in games 3 and 4 on the road, respectively, and 54.4% over the last three quarters of game 5 to close out), it seemed that the Spurs had defied the age-old quote, “defense wins championships.” But looking at the defensive rating, I was surprised to see that during the 2013-14 regular season, the Spurs had once again ranked in the top 3 for defensive rating, as well as 6th for opponent points per game. In fact, the Spurs have shored up their defense over the last two seasons after ranking 16th for points allowed during the 2011-12 season. While the Spurs have fine-tuned their offense over the years, defense has always been a part of the team’s identity, and they proved it again this season.
A Balanced Attack
It’s hard to believe that just one or two seasons ago, many NBA fans considered the Spurs the boring team that no one wanted to watch. Equipped with a so-called “boring” superstar in Tim Duncan, this Spurs team has thrived on staying out of the media limelight. Duncan has always been a man of few words, and his successor as the franchise player, 2014 Finals MVP Kawhi Leonard, has shown himself to be the same way in his three short seasons in the league.
Yet, on the court, the Spurs have become the team to watch this past season, and not because of any one player, but because they play the best team basketball in the NBA. The unselfishness with which they play the game has led the Spurs system to be dubbed the beautiful game. And that unselfishness, ball movement, and passing is reflected in the numbers. The number of win shares (a metric for attributing a team’s success to individual players) for the player with the highest win share on the team has decreased since the 2001-2002 season, when Tim Duncan had the most win shares on the team with 17.8. By contrast, this past season, Kawhi Leonard led the team with 7.7 WS, but Duncan was right behind with 7.4, with four more players with over 5.5 WS.
Similarly, another indicator of the balance of the Spurs offense is the assist numbers. The Spurs averaged 25.2 assists per game this past season, the highest of the Duncan-Popovich Era. Perhaps more telling is that future Hall of Fame point guard Tony Parker had the most APG of any player on the Spurs team, but still only averaged 5.7 APG, translating into 32% of the team’s assists when he was on the floor. By contrast, Los Angeles Clippers point guard Chris Paul averaged 10.7 APG this past season and an assist percentage of 49%. This is not to take away from Tony Parker’s ability, but rather to show how the entire Spurs roster shares the responsibility for playmaking and passing. In fact, the third and fourth highest APG on the roster go to two big men, Duncan and Boris Diaw who, along with Tiago Splitter, form one of the deadliest passing front courts in the league. Spreading the wealth took on a new meaning this season, with 5 players on the Spurs roster who averaged double-digit scoring, and another three averaging over 8 points per game. By comparison, the Miami Heat only had three players who averaged double-digit scoring and only two others above 8 points per game. Keep in mind also that no player on the Spurs roster averaged more than 30 minutes a game during the entire regular season.
Lessons Learned: Defense Still Wins Championships
Thinking back to the 2012 NBA playoffs, there was pretty strong cause to believe that the Spurs were going to win it all: they went into Game 3 of the Western Conference Finals against the Oklahoma City Thunder up 2-0 in the series and riding a 20-game winning streak dating back to the regular season. But, they lost the next four games in a row. Interestingly, that season was the low point for the Spurs defense. That year, they ranked highly in almost all the offensive statistics (FG%, 3PT%, and PPG in particular), but they were below the league average by quite a few defensive metrics, including Opponent FG%, Opponent Points Per Game, and Opponent FG Attempts Per Game.
Since then, the Spurs have made more of an effort to shore up their defense, and it has paid dividends. Both the 2012 Spurs and 2014 Spurs teams were offensive machines, but the 2014 Spurs differed in that they had a stronger defense. What’s most striking to me after looking at this data is how underrated the San Antonio defense was this year, especially in the media. One of the biggest changes that the Spurs made after losing to the Heat in the Finals last year was their defensive strategy. Instead of giving space to Lebron and Dwyane Wade and enticing them to shoot, this year the Spurs played them close, forcing them to create shots and drive the ball. In Game 7 last year, it was their defensive strategy that backfired when Lebron started hitting all those open shots. This year, they flipped the script, and it worked. While it was still the Spurs offense that brought in the fans and had analysts raving, at the end of the day, defense still wins championships.
Where do the Spurs go from here?
The Spurs bounced back from their crushing loss in the 2013 Finals to the Heat with a dominant performance this year. Tim Duncan and Gregg Popovich won their fifth rings together and have nothing left to prove. But, all the key figures in the Spurs organization have signed up to come back next season, and there’s no doubt in my mind that they will be contenders once again. The tandem of Tim Duncan and Gregg Popovich has been the foundation of the franchise for 17 years, and the Spurs’ consistency can be attributed to their adaptability through the years. People have been writing off the Spurs for years, especially after their first-round loss to the Memphis Grizzlies in the playoffs in 2011 and their collapse against the Oklahoma City Thunder in the 2012 Western Conference Finals. But, the team continues to prove the doubters wrong, and history suggests that the Spurs will retool their roster and refine their system again next season as they try for the same result. If you are a fan of basketball, there is no way you can call the Spurs boring; I, for one, can’t wait until October to see the “beautiful game” once again.
Concluding Thoughts on Basketball Analytics
The NBA eye test and basketball analytics complement each other in furthering our understanding of the game of basketball. Now, with free data visualization software like TableauPublic, analytics has become even easier for sports fans and stats geeks alike. The interface is easy to pick up, there are great tutorials online, and there’s so much data to be explored, regardless of what interests you. You don't have to rely on ESPN for your analysis -- I encourage everyone to try out TableauPublic and see if you can find something interesting from the data.