The Ignored Value of the Blocked Shot

Momentum is defined by Merriam-Webster as “strength or force gained by motion or through the development of events.” As the most finite definition I could find, that’s not very measurable, yet momentum is used as a subjective measurement in sport all the time. It’s commonly cited when a safety blows up a receiver on a cross pattern in football on 3rd down for an incomplete pass, when a pinch-hitter in baseball launches a solo home run off a team’s closer to set up a big inning in the bottom of the ninth, or when an NBA athlete sends home a monstrous dunk over a helpless defender. Quite possibly, such plays do constitute sufficient motion or development of events to satisfy the definition of momentum, but what statistical difference has been made? In other words, the safety blowing up a receiver is still an incomplete pass, or possibly a pass-breakup. The solo home run is still one run. Statistically, the tomahawk dunk over a 7-foot defender is worth as much as a layup.

Furthermore, given the short time of ball possession in basketball compared to other team sports, in the NBA momentum shifts back and forth at a pendulum-like rate. For example, the Suns’ Steve Nash can flip a dime to Amare Stoudemire on a fast-break who then blows up an unwitting defender for a rim-rattling dunk (often), but any momentum gained by that play seems to be negated, at least to my thinking, by the fact that the opponent who just got dunked on then passes the ball inbounds to initiate a change of possession. Take this hypothetical a step further, however, and say that Steve Nash steals the ensuing inbounds pass and sets up Amare to rattle another rim. There perhaps you can say that tangible momentum has been gained, since Phoenix received an extra possession and score at the expense of their opponents' possession and potential score.

But now let’s muddle this up even more and take this back to square one. Steve Nash flips a dime to Amare Stoudemire on a fast-break who then goes up for that rim-shattering dunk….only to meet a fully extended beast named Dwight Howard at the rim with a hand on all ball. Freeze scene right there. Three things could happen here barring a subjective foul call from a referee (entirely different topic for an entirely different post). Best case for Orlando, Dwight's block on Amare results in a change of possession. Neutral case for Orlando, the block ends up going out of bounds without being touched by anyone, resulting in a dead-ball out of bounds but no change of possession. Worst case for Orlando, an ill-timed or oddly caromed blocked shot by Dwight results in an easier bucket for the Suns than the blocked shot attempt (e.g., the block ends up in the hands of a wide-open Raja Bell beyond the arc who proceeds to drain a three-point shot).

Now we can return to the idea of a change in momentum. Getting your shit swatted by an opponent, for lack of a better term, can be the closest thing that a defender has to a rim-shattering dunk, i.e. “strength or force gained by motion or through the development of events.” The problem is that more often than not a blocked shot results in no change in momentum at all in that ball possession does not change, and in some cases a blocked shot may even hurt the defending team by resulting in an easy bucket for the opponent. Swatting a shot out of bounds with all the anger of Zeus behind you does nothing except stop the clock. Swatting a shot to an even more wide open opponent than the victim of the block results in a negative change in momentum. But, blocking a shot and taking possession, well that is literally gaining a blocked shot and a steal in one play, which to my mind is the most positive gain in momentum that a defending team can achieve.

Unfortunately, in terms of statistics the NBA does not analyze a blocked shot in this way. A blocked shot ends up being tallied in the B or BS column of the boxscore. One of your host's colleagues has pointed out that the NBA now includes blocks against (BA) in their online boxscores, which indicates how many times a player has his shot attempts blocked in a game. This is a welcome addition, but the NBA is still missing out on the real statistical value inherent to a blocked shot. For that, your host believes that NBA statisticians should begin keeping tracks of the inverse of blocks against. This could be called BTT (Blocks-to-turnover) which would indicate the number of blocked shots by an individual player that resulted in a change of possession once the loose ball is secured. Before this goes any further, a disclaimer: statistics, for all their supposed objectivity of numbers can be useful tools but do not necessarily lead one to the most objective perspective. Nonetheless, with BTT, one is better equipped to judge a post player on whether he blocks shot intelligently or simply gets off on swatting peoples’ cookies three rows deep in the stands.

Your host did some follow-up research on this by researching the league’s top-3 blocked-shots leaders online as of November 12, 2007 and then scouring/fast-forwarding (a lot) through archived games on NBA league pass for blocked shots and the ensuing results. As it stands, the league’s blocked shots leaders are Denver’s Marcus Camby, Atlanta’s Josh Smith, and Houston’s Yao Ming (in that order). Luckily, by reviewing Denver and Houston’s games I was also able to tally blocked shots for Shane Battier and Kenyon Martin, who as of this post stand in the NBA’s top 50 in blocked shots, respectively, at 23rd and 30th.

Here are my findings:


Marcus Camby - 22 blocked shots, 15 BTT, 31.8% blocks lost or no change in possession

Josh Smith - 21 blocked shots, 6 BTT, 71.4% blocks lost or no change in possession

Yao Ming - 19 blocked shots, 7 BTT, 63.2% blocks lost or no change in possesssion

Shane Battier - 8 blocked shots, 5 BTT, 37.5% blocks lost or no change in possession

Kenyon Martin - 7 blocked shots, 1 BTT, 85.7% blocks lost or no change in possession


I’ll be the first to admit that these stats should not hold a lot of weight given the small sample size (as of the timing of this post, none of these players had yet to play 10 games). That said, two statistical trends are clear: 1) Josh Smith and Kenyon Martin’s blocked shots have not translated well to a change in possession; 2) Marcus Camby and Shane Battier’s blocked shots have translated well to a change in possession. So that leaves me asking in the case of Smith and Martin - What have all your blocked shots done other than enter the statbooks as a blocked shot?

Part of this discrepancy can be attributed, I think, to style of play. This was clear in revewing the archived games. Smith and Martin are high-flying shot-blockers with a penchant for blocking shots in the transition game and adding extra 'oomph' to their blocked shot attempts. This combination results in a high percentage of blocked shots that become loose balls either on the perimeter or out of bounds. Camby and Battier, on the other hand, are more straight-up shot blockers who do most of their defensive dirty work against half-court offensive sets. In terms of shot blocking, low-post situations more often result for a fight for loose balls in the paint.

Yao is an interesting case in that while he blocks a lot of shots, a disproportionate amount of his blocks ended up going right back in to the hands of the player who was the victim of his block. I think this is due partially to his relative lack of mobility compared with smaller, faster players. Yao Ming is a great center for his size, but obviously, chasing down loose balls is not his strength.

So that brings us to the end all of statistical value- What does this all mean and why should we care? Both the danger and the value of statistics are the same - they help compress all of the details of a basketball game into a cognitive impression based upon tangible numbers. Statistics allow casual fans to pass judgment on the value of a player (not necessarily a good thing), while allowing die-hard fans to either confirm or deny what they've seen take place on the basketball floor (not necessarily a bad thing). While watching an NBA basketball game, so often we are so transfixed by the intimate display of athleticism before our eyes that we overlook or ignore the nuances of the action taking place before us. Useful statistics make those nuances tangible so that we can measure intangible things such as momentum.

In my personal experience, Marcus Camby shattered my predisposed opinion going in to this small sample study. No one doubts that Camby blocks a lot of shots (he’s averaged 2.5 per game over an 11 year career, with four of his five best BPG years coming in the last four seasons). Nonetheless, I always thought of Camby as more of a “I’m gonna git you sucka and swat your shit to neverland” kind of center. From the games I watched, that was not the case. Perhaps its veteran savvy, or perhaps it’s knowing that he has quick and rangy teammates such as Nene, K-Mart, Melo and AI to gobble up loose balls, but Marcus Camby is a VERY INTELLIGENT defender along with being a gifted athlete. His footwork and positioning under the hoop when a shot goes up is impressive, and as this statistical study demonstrates, two out of three of his blocked shots result in an additional possession for his team. You cannot say the same about his teammate K-Mart thus far.