The Kobe Assist
Introducing a new NBA statistic that proves that missing shots is sometimes just as valuable as making them
By Kirk Goldsberry on December 6, 2012PRINTLate in the second quarter of the Kings and Lakers game on October 21, something ordinary but deceptively important happened. With the Lakers in their half-court set, Dwight Howard set one of his monstrous picks along the right wing to free up Steve Nash, who has led the NBA in assists six of the last eight seasons.
Nash used the screen to get past Isaiah Thomas and head toward the right corner; he took one dribble with his right hand toward the corner, switched directions, employed a crossover, and by the time his second dribble arrived back up in his left hand he'd landed near the right elbow with the Kings defense collapsing upon him. He recognized this immediately and launched a beautiful left-handed pass in midstream to the left wing, where Kobe Bryant awaited. Kobe was wide-open; he caught the ball and shot without hesitation. He missed, and despite the great screen by Howard and the great playmaking by Nash, this beautiful basketball sequence was seemingly fruitless. Nash would not get his assist.
However, while Nash was busy playmaking and while Kobe was busy jump shooting, Dwight Howard had taken about seven steps toward his happy place — the restricted area — fought off the gigantic DeMarcus Cousins, and gained optimal rebounding position. Kobe's miss ricocheted upward from the rim before descending back down into the hands of Howard, who quickly put the ball in the basket; the Staples crowd went wild (in the dark). Did Kobe just miss a shot or did he just inadvertently set up Dwight Howard for an easy score? Are some of Kobe's missed shots actually good for the Lakers? Are some of his misses kind of like assists?
Basketball is a game of sequences. Unlike baseball or football, it is a relatively continuous free-flowing sport. The actions within a game are hard to separate because they are chronologically intertwined, and every event in every game is influenced in part by preceding sequences of actions. Every game is its own ecosystem characterized by teamwork, athleticism, and frequent episodes of magnificence. But the same things that make basketball so captivating to watch also make it more difficult to measure and to analyze.
Most basketball statistics refer to discrete events such as shots, steals, and rebounds that occur within the continuous context of a flowing game. Basketball is very different from baseball, but in the basketball analytics world, too often we treat our sport as if it were baseball; we kid ourselves and say a rebound or a corner 3 is akin to a strikeout or a home run, a singular accomplishment achieved by a player that's fit for tallying and displaying in a cell on some spreadsheet on some website.
But, unfortunately, it's not that simple. In reality we all know crediting a wide-open corner 3 solely to Matt Bonner, Kawhi Leonard, or Danny Green is akin to giving Javier Bardem sole credit for No Country for Old Men. Bonner, Leonard, and Green get great looks because of the splendidly directed, infinitely complex ecosystem that is the San Antonio Spurs offense. Over the last two seasons Matt Bonner has made 210 out of 480 3-point attempts (44 percent), which is incredible. However, how would these numbers differ if he played for the Wizards? Corner 3s are more like touchdowns than they are like strikeouts. They are punctuation marks at the end of complex strategic sentences. We may be really good at tallying those punctuation marks, but we are not so good at diagramming or even understanding those sentences; within our box scores and spreadsheets we are failing to give credit where it is due.
Just as the theoretical butterfly flapping its wings in Rio somehow influences the formation of a faraway hurricane, basketball outcomes exhibit sensitive dependence on previous environmental conditions, yet the analytical "baseball-ification" of our fluid sport too often neglects this basic tenet of basketball ecology. We disregard too much environmental context. As an illustration of how this baseball-ification of basketball ecology can hinder our understanding, consider the Kobe Assist, those missed shots that are more like accidental passes that lead to put-backs.
Jump shooters are the butterflies of the NBA, and each time a shooter releases a shot, a fascinating sequence begins to unfold. Depending on who is shooting, where on the court they are shooting from, the stratagems of each team, the rebounding abilities of each player, and the precise spatial configuration of the 10 players on the court, shot outcomes vary considerably. On the imaginary road map to a shot's outcome, the first fork in the road is the most important: Did the shot go in, or did it not go in? This is a vital and obvious thing to measure, and we do this pretty well with things like field goal attempts, field goals made, and field goal percentage. However, a shot's story arc does not begin at its release nor does it always end at the hoop. What happens after a missed shot is very important and directly related to the same set of environmental conditions on the floor that provided both the original context for the shot and the influential factors that determine what happens next. Conventional basketball metrics segment continuity too much. We quarantine the chicken from the egg; we divvy basketball events so much that we ignore obvious relationships between shooting environments and shot outcomes.
Missed shots are kind of like informal jump balls that happen dozens of times per game. Instead of a referee gently tossing the ball up in the air, some random ricochet off of the basket breaks the bad news to the offense, propels the ball skyward, and for a few moments the ball is disowned and its possession is literally up for grabs. But just like shot outcomes, rebounding outcomes also depend on who is shooting, where they are shooting from, the stratagems of each team, the rebounding abilities of each player, and the precise spatial configuration of the 10 players on the court; as a result, there is a less apparent tenet of basketball: All missed shots are not created equal, and their DNA is inherently dependent upon their ancestral events — some missed shots are good for the defensive team, and some benefit the offense, as many misses actually extend offensive possessions with the proverbial "fresh 24."
This is where the Kobe Pass — a necessary predecessor to the Kobe Assist — comes into play. I define the Kobe Pass as the missed shot that begets an offensive rebound and thus extends an offensive possession. Of course, offensive rebounds are an important statistic on their own, but sole credit for an offensive rebound is traditionally awarded to the player who acquires the rebound. Little else is considered. We conceptualize them as destinations but ignore their origins. Where do offensive rebounds come from?
Offensive rebounds are constructive offensive events that frequently result in a big basketball player possessing the ball very close to the goal. They are like surreptitious but extremely effective entry passes. In fact, league-wide, 34 percent of the time Kobe Passes result in points right away because the recipient of the Kobe Pass, a.k.a. the offensive rebounder, frequently scores immediately after acquiring the basketball. In such cases, I define the Kobe Assist as an achievement credited to a player or a team missing a basket that in a way leads directly to the kind of field goal generally referred to as a put-back, tip-in, or follow.
Many times these field goals shape the outcomes of basketball games, but we neglect to consider what exactly they follow. We fail to explore the interactions between shot events and put-backs. We fail to understand which shooting environments are most or least conducive to offensive rebounds. We only kind of know which players' and teams' missed shots are most likely to result in put-backs. Most important, we have no idea who leads the NBA in Kobe Assists.
Spoiler alert: Kobe Bryant is the king of the Kobe Assist and hence its namesake. Over the last two seasons, Kobe had more than 200 Kobe Assists, which is by far the most in the league and also precedes the arrival of Dwight Howard, the most dominant interior presence in the NBA. The combination of one of the league's most voluminous and creative jump shooters with the league's most dominant interior force will only proliferate the Kobe Assist phenomenon in L.A.
While Kobe haters may delight in the idea that many of Kobe's best passes are actually his missed shots, I would suggest that these folks temper their delight because, like it or not, these passes are effective. I would also argue that many times Kobe Assists are not as accidental as they may seem; in fact, the belief that these outcomes are "lucky" or these bounces are "fortuitous" diminishes the considerable skills required for an offensive team to extend a possession or score those critical "second chance" points. A 16-foot jumper during a fast break is a horrible shot in part because there is little chance a teammate is present in case you miss; that same jumper in a half-court set when Dwight Howard and Pau Gasol are on your team and near the basket is nowhere near as foolish. The latter is the actual shooting environment in Los Angeles; this is the ecosystem where Kobe Bryant lives.
As a general rule, NBA offenses rebound 32 percent of their misses. But this number is not homogeneous league-wide; it depends on the team, the shooter, and many other variables — especially team priorities. The Celtics, who famously prioritize transition defense over offensive rebounding, only rebound 23 percent of their misses, while the high-flying and physical Denver Nuggets capture 42 percent of their missed shots. The Lakers prioritize offensive rebounds, and given their personnel that makes a lot of sense for them.
As of November 30, Kobe has attempted 289 shots. He has missed 146 of them, but the Lakers have retained possession on 50 of those misses. Furthermore, the Lakers have immediately converted 22 of those 50 offensive rebounds into points. So far this year, Kobe has 22 Kobe Assists, which trails only Dion Waiters and Carmelo Anthony. You might be saying, "Well, since Kobe shoots so much, this isn't that special." Not so fast — 15 percent of Kobe's misses immediately lead to Lakers put-backs, which is much higher than the league average. In comparison, Dallas's Vince Carter has missed over 100 shots and only has three Kobe Assists all year. The Lakers have a smarter, more responsive jump-shooting environment than almost any other team in the NBA.
But some of Kobe's misses are even more "effective" than others. So far this season, Kobe has taken 107 close-range shots (within 7.5 feet). He's made 59 percent of them, which is very good, but what is scary is that of his 44 misses in this zone, the Lakers have rebounded 52 percent of them, and immediately put back 32 percent of them. Breaking it down this way raises provocative questions about how we evaluate shooting in the NBA. Out of 100 close-range Kobe shots, 59 go in and 41 miss. Of those 41 misses, the Lakers grab 21 of them; the defense grabs only 20 of them. This means 80 percent of Kobe's close-range shots either result in immediate points or a "fresh 24." Furthermore, out of those 44 misses, 14 will become "put-backs" — so, out of 100 close-range Kobe shots, 59 immediately find the net and 14 more find the net within seconds of being rebounded by a Laker; 73 percent of Kobe's close-range shot attempts become points for the Lakers within five seconds.
Around the league this season, there are other examples of effective misses. Cavs rookie Dion Waiters provides a fascinating case. He's making 36 percent of his 3s so far this season, which is average, but incredibly the Cavs have rebounded 35 of his 54 misses (65 percent) from beyond the arc. Elsewhere, the Knicks put back close-range misses by Carmelo 35 percent of the time. Of course, these high numbers have a lot to do with Anderson Varejao and Tyson Chandler, who are both dominant rebounders, but it's not that simple. The presence of a dominant rebounder does not ensure Kobe Assists. The Rockets have only put back 8 percent of James Harden's 147 missed shots this season despite the presence of Omer Asik, the league's third leading rebounder. Kobe Assists also depend on shot location. Although the Knicks love to rebound and put back Carmelo's close-range misses, they very rarely put back any of Carmelo's mid-range misses, and Knicks fans' subconscious knowledge of this may explain their groans about mid-range Melo. By conventional numbers, Carmelo is a fairly average jump shooter and a slightly above-average close-range scorer, but when we look more broadly at the basketball sequences these numbers take on a completely different tone. The Knicks rebound 55 percent of his close-range misses but only 14 percent of his mid-range misses. When he is close to the basket, good things happen that field goal percentage will never be able to explain. All Carmelo misses are not created equal.
As another example, consider the cases of Elton Brand and Derrick Rose. Conventional wisdom suggests Elton Brand is a better mid-range shooter than Derrick Rose. Over the last two seasons Elton Brand made 381 out of his 782 mid-range jumpers (49 percent). This is really impressive because as a whole the league shoots only 38 percent from mid-range. During the same window, Derrick Rose made 294 of his 724 mid-range shots (41 percent), which isn't bad, but it's much closer to average than to elite. Again, field goal percentage does not tell the whole story. The Bulls rebounded 152 of Rose's 430 misses (35 percent), while the Sixers rebounded only 63 of Brand's 401 misses (16 percent). Looking at these shots through another lens, 62 percent of Rose's mid-range shots result in points or a fresh possession for the Bulls. For Brand, 57 percent of his mid-range shots result in points or a fresh possession for the Sixers. Which is better?
The Rose-Brand comparison suggests that by appending offensive rebounding rate or put-back rate to field goal percentage we can more accurately assess a shot's true value. Every time a shot is released, a potential change of possession gets its wings. An additional reason close-range shots are more effective than mid-range shots is that, when missed, they are rebounded by the offensive team at much higher rates; in other words, they kill possessions at lower rates than jump shots.
You can also think of Kobe Assists as delayed makes. This way it's also easy to reevaluate an individual shooter's shooting efficiency. Our dominant shooting analytic is field goal percentage, which is essentially the number of made shots per 100 attempts. Well, if we extend our temporal window of analysis to account for these delayed makes, we can start to make interesting new inferences about overall shooting efficiency.
Every offensive rebound comes from somewhere. More specifically, every offensive rebound follows a missed shot that was attempted by an offensive player somewhere on the court. By neglecting to evaluate the contrails of offensive rebounding events, we shortchange our understanding of the game. Take, for example, the game's best pure rebounder, Kevin Love, who has recently become a more prolific 3-point shooter. However, when Love takes a 3-point shot he is obviously not in a great rebounding position. As a result, Love's 3-point attempts elicit fewer offensive rebounds and Kobe Assists than those of his teammates. Over the past two seasons, the Wolves have rebounded their own 3-point misses 26 percent of the time. But this number for Love is 20 percent — it's 30 percent for Luke Ridnour. So, while looking at the surface of field goal percentage, Kevin Love seems to be a decent 3-point shooter, but when we examine the sequential nature of the Timberwolves' 3-point shooting his attempts are less efficient than many of his teammates.
Although the smartest basketball analysts evaluate success by possessions, for the most part the temporal extent of basketball analysis remains too narrow. Anyone who has ever acknowledged that the "assist" has some value has therefore admitted that basketball outcomes exhibit sensitive dependence on the events immediately preceding them. But this concept goes well beyond passing, is central to basketball strategy, and is part of what separates basketball from other games we love to measure. Baseball analytics had its epiphany in part because Bill James and others realized that baseball was only barely a team sport, and really could be reduced to a discrete sequence of outcomes that involved singular players competing in sequences of one-on-one scenarios. But basketball achievements do not occur in a vacuum; just as it is rare for one player to be solely responsible for a made basket, it is similarly rare for one player to be solely responsible for other types of events, including rebounds and put-backs.
Although Kobe Assists are admittedly a silly reminder of the natural connectedness of basketball plays, they also provide a real diagnostic of how well offensive ecosystems cooperate. In the taxonomy of the NBA, there are various species of superstars. Different players do different things, and as evidenced by the league's great offenses, like the one in San Antonio, the best teams are the ones that somehow find a way to be greater than the sum of their individual parts. When you step back and think about combining Steve Nash, Kobe Bryant, and Dwight Howard it seems obvious that they would coalesce to become a ridiculous collective scoring device, yet look no further than Mike Brown for proof that this is easier said than done. As Kobe eclipses the 30,000-point milestone, we're reminded of how great a scorer he was, and still is. There's no doubt that Kobe is still the king of the Lakers' offensive ecosystem, and it's up to the Lakers' coaches to devise schemes that both acknowledge and optimize this. Kobe shots will happen, and they will happen a lot, but what happens after them may determine the outcome of this Lakers season.
--------------------------------------------------------------------------------
