The value of Tim Duncan’s blocks


Henry Abbott, Kevin Arnovitz, and numerous other TrueHoop Network writers are at the MIT Sloan Sports Conference. While there, Sebastian Pruiti of NetsAreScorching and NBA Playbook reported on a paper presented by John Huizinga, a professor of business at the University of Chicago (via TrueHoop):

Is blocking a lay-up more valuable than blocking a jump-shot?  Mr. Huizinga’s data says yes.  In his presentation, he said that it all comes down to expected value.  A jumper has an expected point value of 1.04 while a lay-up has an expected point value of 1.54.

Although intuitive in its own right, this information paints a counterintuitive portrait of some of the NBA’s better regarded frontcourt defenders. For instance, “Looking at it this way, Brendon Haywood, who many people think is a very good defender (me included) actually is a less valuable shot blocker than Jermaine O’Neal.”

Huizinga’s paper is titled “The Value of a Blocked Shot in the NBA: From Dwight Howard to Tim Duncan,” and not without good reason, explains Pruiti:

…As [Huizinga] explained, through a series of charts, Tim Duncan has had the best season in history when it came down to value/block with 1.12, meaning he saved 1.12 points with every block and Dwight Howard ended up with the worst season in terms of value/block with with .53 (both came during the 2008 season).

Long ago I noticed that most of Tim Duncan’s blocks came right at the rim, which is why I am so excited to read about Huizinga’s paper. Rather than stoke the debate between traditional scouting and advanced statisticians, it further shows how the conclusions of one can work symbiotically with the visual evidence of the other.

  • Joe

    At least based on this blurb, Prof Huizinga’s data suggesting that Timmy is one of the most effective shot blockers in history doesn’t even seem to address the fact that Timmy is also one of the best ever in controlling the ball after the block. Not that this is news to the readers here, but it’s always nice to see others talking up Timmy.

  • Anthony McDonald

    Seems like a lot of number crunching to tell us what we already knew — Duncan is the greatest PF of all time! Also, those numbers don’t account for something even more important…..How many times did the shot blocker’s mere presence stop an opponent from driving or made them shoot earlier?

  • Graydon Gordian


    It’s interesting you bring that up. I can’t be sure, as I haven’t read Huizinga’s paper yet, but I imagine his “block value” is a bit incomplete if it doesn’t include a concern for who possesses the ball after the block. The Spurs often collect the ball after one of Duncan’s blocks.

    Pruiti had this to say about Huizinga’s formula:

    “To determine block value, he used the formula Points Saved + Points Created where Points Saved equals the effect of a Block on Opponents Expected Points during this possession and Points Created equals the effect of a Block on Own Team’s Expected Points During the next possession.”

    The last section of that– “expected points during the next possession”– suggests to me that what happens post-block is taken into consideration by Huizinga.

  • lvmainman

    Interesting that Ratliff in this paper is mentioned as a valuable shot blocker, but the Spurs determined that Ratliff wasn’t valuable to be used as a shot blocker.

  • muwu

    Uh, it mention Ratliff having the best block rating season in 2003. The present calendar year is 2010.

  • Nadeem

    Completely off topic, but the Spurs were apparently stuck in SA last night and had to fly this afternoon.

  • Colin

    Great point that Joe brings up. Bill Russell is the best all time at that skill as well as best outlet passer of all time. While I wouldn’t compare Duncan to Russell in that regard, they are comparable.

  • Colin

    …..sorry, a bit redundant with my use of words there. I meant to say that Russell and Duncan are in the same sentence with their defensive skill sets.

  • Jim Henderson

    After winning our 3rd straight game, and before tonight’s road game against the Grizzlies, I decided to take a brief look at the Spurs wins & losses season-to-date, with a couple of specific questions in mind:

    (1) How many “win streaks” have we had this season (using quite modest criteria of “at least 3 straight wins”), and are there any notable patterns?

    (2) How have we done in “winnable” games (defined as “decided by less than or equal to 8 pts.”), and again, are there any notable patterns?

    First, on the “win streaks”:

    – we’ve had only 5 “win streaks” the entire season; three of them were “3 game streaks”, and two of them were “5 game streaks”.

    – won 5 straight end of Nov.; 4 of the 5 were at home, 3 of 5 against sub-.500 teams; the other 2 were against .500 teams (within 2-3 games of .500).

    – won 3 straight mid-December; 2 of 3 at home, 2 of 3 against sub-.500 teams, and the other against a .500 team).

    – won 3 straight later-half December; 2 of 3 at home, 3 of 3 against sub-.500 teams.

    – won 5 straight end of Dec. – 1st wk. Jan.; 3 of 5 on the road, 4 of 5 against sub-.500 teams; the other against a .500 team.

    – current 3 game streak; 2 of 3 at home, ONE against PLUS .500 teams; 2 against .500 teams.

    As you can see, our “streaks” are quite limited in duration, they occur prohibitively at home, and against sub-.500 & .500 teams.

    IF WE WERE TO WIN TONIGHT, it would be the first “streak” this season that included a PLUS .500 team AND at least half of the streak occurring ON THE ROAD. With our upcoming schedule (heavy ROAD & PLUS .500 teams), this will be a critical test this evening against a “game” Grizzly team.

    Our record in “close” games (see criteria above):

    25 games

    Lost – 15

    Won – 10
    4 against sub-.500 teams
    4 against +.500 teams
    2 against .500 teams
    5 at home
    5 on the road


    .400 win percentage in ALL “close” games.

    As you can see, this is a POOR record in close games. The “big three” will need to start leading the way in closing out games with better offensive execution, making big plays, & clutch shots. Overall team CONFIDENCE to close out games must improve during the remainder of the team’s schedule, otherwise it’s gonna get ugly as we complete a difficult season.

  • Nadeem

    Bad news….Tony breaks fourth right metacarpal. Might be out for at least a month.


  • David G

    Is this paper available anywhere? Cool to see Rasho on the value block list!

  • Beverly

    Tim is still the main man of the Spurs. I STILL BELIEVE!!!!! 2010 THE YEAR OF THE SPURS!!!!! GO SPURS GO!!!!!

  • Cal

    This one of the reasons sports fans don’t like these advanced statistics they don’t really make that much sense and there is always something that can’t be taken into account (intemidation factor) and the obivious one is that there is no way of telling whether the shot would have went even the layups.