The Value of an NBA Block — Statistically Speaking
The idea is not to block every shot. The idea is to make your opponent believe that you might block every shot. — Bill Russel
The block in basketball has long been a cornerstone in player highlight reels and a fundamental metric in a players’ defensive capabilities. However throughout Covid-19, without any live sports to watch, I and my good friend and roommate Jeremy have spent a little too much time watching old highlights and games. As time went on, we, like many other bored teenagers, began watching click bait YouTube videos that nobody can resist such as “Greatest NBA Blocks,” and “Most clutch shots in NBA history”. Following one of many “Greatest Blocks” videos, we noticed a pattern, that is, that so many of these blocks, particularly from the 2000’s era swat-blockers, ended up out of bounds. This made us wonder how valuable a block really is. So, we did what any curious student would do, we logged 9,602 NBA blocks off of NBA.com game logs from this season into excel, and did some analysis.
We created a dynamic excel model, recording data with binary variables to best generate statistics, and recorded whether the block led to an o-board or d-board [P(O — Board)], whether the team scored given they receive an O-board [P(Point | O. Board)], as well as the tendencies among teams following an O board [P(score | 2 pointer)], and [P(miss | 3 pointer)]. With this basic set of data, along with some analysis, we came to some interesting conclusions.
The Results
The data, upon a surface-level analysis, told us nothing new: blocks are a good thing. Based on the data we analyzed, the average block will lead to an O-board 41% of the time, and of that 41% of O-boards, 39.3% lead to points. If you were to take these probabilities and multiply them by the average shot attempted — and point scored following an O-boards, you would come to find that the average points per possession given a block is 0.27. This is nearly a quarter of the average NBA points per possession, which is much higher at 1.09. So to nobody’s surprise, the data tells us the obvious, blocks are a good thing. Nonetheless, we’re not done here as we haven’t solved our original question, and after further siphoning through data and honing in on specific variables, we came to various surprises and interesting data points.
2000’s era blockers
What was previously indisputable is now evident, blocks are valuable, but are some blocks more valuable than others? More specifically, when someone like Dwight Howard, who (it appears) often swats the ball out of bounds leading to an O-board block the ball, is that of any value? Once again, the answer is yes. To use Howard as an example, to my surprise, when Howard blocks the ball, the probabilities of the block leading to an O-board, as well as said o-board being converted into a point, were within one to three percentage points of the mean, displaying no real variation between Howard’s blocks, and all other blocks. So that answers our first question, that Dwight Howard, a typical sweat-era blocker, has no higher o-board percentages than the league average. Below is a list of some of the top rim protectors in the league, along with the statistics surrounding their blocks.
All of the data tells a relatively similar story, that is, in being a top ‘blocker’ in the NBA, your blocks are more valuable. As such, all of these players stand out as being predominantly below average in the best of ways.
The only true anomaly is Hassan Whiteside. Interestingly, Whiteside has a reputation of being a ‘lazy’ player, who often lacks consistent hustle. In this case, this data further enhances this narrative, highlighting what may very well be a frequent occurrence in which Whiteside blocks a shot, and, for whatever reason, does not hustle for the rebound, thereby handing the opposing team a high percentage shot. Furthermore, Whiteside’s percentage of blocks leading to O-boards, as well as O-boards followed by points were numerous percentage points above the mean and were in the top 5% of all NBA players within these categories. Ignoring Hassan however, these statistics confirm a preconceived notion that the best shot blockers are not only effective but that their blocks are more valuable.
In addition, one player who stood out among the group of shot blockers, was, ironically enough, the shortest player in the list above. Two time Defensive Player of the Year Kawhi Leonard. And to add insult to injury to the other 7 footers, Kawhi’s numbers stood out not only among the ten players above, but among all players. The low point percentage given an O-board, along with criminally low points per possession remained in the bottom five percent of all players who have recorded at least five blocks during the 2019–2020 season and in doing so, highlighting two key facets of Kawhi’s game.
Firstly, it shows the impact not swatting the ball has on Kawhi’s game, as more than most players with his frequency of blocks, he quite rarely intentionally swats the ball out of bounds, leading to a greater chance for a stop on defense following the block. This can partially be due to his lack of ego on the court, while also keeping in mind that the scenarios in which Kawhi gets blocks differs from most centers strictly due to varying positions. Secondly, it shows hustle. The stats reflect Kawhi, among other players with similar numbers, hustles to get rebounds and follow up blocks with continuous defense.
Other notable statistics
One interesting statistic we came across was the Houston Rockets — post-Clint Capela. Following the Capela trade, when the Houston Rockets block a team and they get an O-board (a greater occurrence post-Capela), the opposing team’s shooting percentage is nearly 20 percentage points below the mean, leading to a much lower point per possession when blocked by the Rockets. This statistic, in particular, is quite interesting as it shows another side of the Houston Rockets, one that stats typically don’t show, namely — hustle. This statistic shows that despite team’s recovering the ball a greater amount when being blocked by the Rockets, the Rockets hustle to such a large extent on defense, that they significantly lower the opposing team’s shooting percentage. They do so to such a large extent such that despite a lack of a true center, they more than compensate in hustle.
Concluding thoughts
We can’t conclude without acknowledging just how much more being a shot-blocker affects the game than the block itself. For most players, seeing someone like Dwight Howard or Rudy Gobert in the paint is enough on its own to cause them to adjust or rethink their play. The presence of a shot-blocker, along with the other ways in which they affect the flow of the game beyond blocking shots cannot be understated. This is important as this is a stat which most statistics fail to identify. Most importantly, shot-blocking isn’t going anywhere. No matter what critics say, if a player gets the opportunity to block a shot the data is, unnecessarily so if I might add, indisputable that blocking shots is a good thing. Should you avoid swatting it if you can, yes, 100%. Nevertheless, the importance in contributing to the best of your ability not only for the block, but following is equally evident in players such as Hassan Whiteside, whose blocks are of less value than that of the average player, and when the Trailblazers lose by one, lose by two, it only makes you wonder… Nevertheless, despite Whiteside having a higher opponent scoring percentage when blocking than the mean, his blocks still yield a much lower opponent score percentage than during possessions in which the ball is not blocked.
In addition, we also learn from this that the concept “height don’t measure heart” applies to basketball equally as much as it does in baseball. Kawhi Leonard and the Houston Rockets are just two examples that demonstrate the extent to which players and teams hustle and fundamentally outwork their opponent to such an extent that it supplements for, and in this case exceeds the effectiveness of many other players with natural advantages.
For more information regarding the raw data, along with inquiries into the statistics and validity of the report, please feel free to message Harrison Berman or Jeremy Klotz on LinkedIn.
