Loading ...
Sorry, an error occurred while loading the content.

My Version 2 of WINVAL

Expand Messages
  • dan_t_rosenbaum
    This version is possessions-based (and thus accounts for pace) and also includes offensive and defensive ratings. In order to make it easier to read, I just
    Message 1 of 5 , Feb 28, 2004
    • 0 Attachment
      This version is possessions-based (and thus accounts for pace) and
      also includes offensive and defensive ratings.

      In order to make it easier to read, I just included it and my
      comments on it on a web-page that I created. Here is the link.

      http://www.uncg.edu/bae/people/rosenbaum/NBA/winval1.htm

      (This thing has almost turned into a mini-paper.)
    • igor eduardo küpfer
      From: dan_t_rosenbaum To: Sent: Sunday, February 29, 2004 1:45 AM Subject: [APBR_analysis] My Version 2
      Message 2 of 5 , Mar 1 12:39 AM
      • 0 Attachment
        From: "dan_t_rosenbaum" <rosenbaum@...>
        To: <APBR_analysis@yahoogroups.com>
        Sent: Sunday, February 29, 2004 1:45 AM
        Subject: [APBR_analysis] My Version 2 of WINVAL


        > This version is possessions-based (and thus accounts for pace) and
        > also includes offensive and defensive ratings.
        >
        > In order to make it easier to read, I just included it and my
        > comments on it on a web-page that I created. Here is the link.
        >
        > http://www.uncg.edu/bae/people/rosenbaum/NBA/winval1.htm
        >
        > (This thing has almost turned into a mini-paper.)
        >

        "Mini"? :-)

        Great stuff, Dan. It will take me a few days to digest the whole thing. A
        couple of comments in passing:

        * <quote>
        Null Hypothesis: the cost of two point FGA is the same as the cost of three
        point FGA

        The null hypothesis is soundly rejected with three point FGA having a lower
        cost, even after accounting for points produced and free throw attempts
        generated.
        </q>

        Would it be asking too much to try this one again, this time including
        rebounds in the accounting? Common Wisdom has it that 3 pointers generate
        more offensive rebounds, which could add to the value of the long attempts.
        (I'm aware that DeanO disputes CW in his book, and I accept his conclusion
        that 3 misses are no more likely to be offensively rebounded than 2 misses.
        Independent confirmation would be very nice, however.)

        * <quote>
        Null Hypothesis: steals and turnovers have the same value, but opposite
        signs

        It is a fairly close call, but the null hypothesis is rejected. It appears
        that steals help teams more than turnovers hurt teams. This could be because
        guys who get steals disrupt offenses in other ways that are not picked up in
        traditional statistics.
        </q>

        Is there some double counting going on here? A steal is always a turnover,
        but a turnover is not always a steal. Is it possible to isolate the types of
        turnovers (steals, bad pass, OFF foul, etc.) in this analysis?

        * <quote>
        Null Hypothesis: offensive and defensive rebounds have the same value

        There is no evidence to reject this hypothesis. Thus, even though these two
        regressions have higher coefficients for defensive rebounds (versus
        offensive rebounds), there really is no evidence to conclude statistically
        that the value of defensive rebounds is higher than that of offensive
        rebounds. That said, it is very, very difficult to draw the conclusion from
        these data that offensive rebounds should be valued higher than defensive
        rebounds, as is often argued.
        </q>

        Still a topic of great interest for me. My opinion, backed tentatively by
        the data I've looked at, is that defensive rebounds have less marginal value
        than offensive rebounds. That is, an individual player's defensive rebound
        adds less to his team's defensive rebounding percentage than that player's
        offensive rebound adds to his team's offensive rebounding percentage. I'm
        not sure if you address this: it could be that DRebs and ORebs add the same
        amount to a team's production, while at the same time saying each _player's_
        O and D rebounds have a different value.




        --
        cheers,
        ed
      • Mike G
        ... attempts... ... Part of the value of a 2-pt attempt is that fouls are created. Part of this value is in the high-% FT that ensue; and part is that fouls
        Message 3 of 5 , Mar 1 4:30 AM
        • 0 Attachment
          --- In APBR_analysis@yahoogroups.com, igor eduardo küpfer
          <edkupfer@r...> wrote:
          > ... Common Wisdom has it that 3 pointers generate
          > more offensive rebounds, which could add to the value of the long
          attempts...
          >

          Part of the value of a "2-pt attempt" is that fouls are created.
          Part of this value is in the high-% FT that ensue; and part is that
          fouls can weaken the opponent for the remainder of the game.

          However, a study that measures blocks of time when certain players
          are in the game will not pick up an effect that removes a player
          from the lineup. By definition, that effect is shifted to a
          later 'time block'.


          > Is there some double counting going on here? A steal is always a
          turnover,
          > but a turnover is not always a steal. Is it possible to isolate
          the types of
          > turnovers (steals, bad pass, OFF foul, etc.) in this analysis?

          My impression is that Dan gets it right to conjecture that each
          Recorded steal is associated with other disruptions by the defense.
          Conversely, a turnover may not be 'all that bad' if it's equivalent
          to a desperation shot; i.e., a desperation clock-fighting pass.

          > .. My opinion, backed tentatively by
          > the data I've looked at, is that defensive rebounds have less
          marginal value
          > than offensive rebounds. That is, an individual player's defensive
          rebound
          > adds less to his team's defensive rebounding percentage than that
          player's
          > offensive rebound adds to his team's offensive rebounding
          percentage...

          Again, each defensive rebound that gets recorded may represent
          several 'assisted rebounds', in which there are several defensive
          players boxing out and otherwise making it easier for one player to
          get the rebound. 3 players may work together to gather 20 rebounds;
          how they officially divide them up for credit, is immaterial to the
          success of the team.

          So each DR recorded may represent several "partial" DR, if such
          things were recorded.
        • John Hollinger
          My research in the 2002 Prospectus showed just the opposite -- that a 3-pointer had LESS chance of being rebounded than a two-point shot. Which makes sense,
          Message 4 of 5 , Mar 1 12:00 PM
          • 0 Attachment
            My research in the 2002 Prospectus showed just the opposite -- that a
            3-pointer had LESS chance of being rebounded than a two-point shot.
            Which makes sense, because coaches are fond of saying the most
            dangerous rebounder is the shooter, and on a 3-pointer the shooter is
            too far away to get most rebounds.



            --- In APBR_analysis@yahoogroups.com, igor eduardo küpfer
            <edkupfer@r...> wrote:
            > From: "dan_t_rosenbaum" <rosenbaum@u...>
            > To: <APBR_analysis@yahoogroups.com>
            > Sent: Sunday, February 29, 2004 1:45 AM
            > Subject: [APBR_analysis] My Version 2 of WINVAL
            >
            >
            > > This version is possessions-based (and thus accounts for pace) and
            > > also includes offensive and defensive ratings.
            > >
            > > In order to make it easier to read, I just included it and my
            > > comments on it on a web-page that I created. Here is the link.
            > >
            > > http://www.uncg.edu/bae/people/rosenbaum/NBA/winval1.htm
            > >
            > > (This thing has almost turned into a mini-paper.)
            > >
            >
            > "Mini"? :-)
            >
            > Great stuff, Dan. It will take me a few days to digest the whole
            thing. A
            > couple of comments in passing:
            >
            > * <quote>
            > Null Hypothesis: the cost of two point FGA is the same as the cost
            of three
            > point FGA
            >
            > The null hypothesis is soundly rejected with three point FGA having
            a lower
            > cost, even after accounting for points produced and free throw
            attempts
            > generated.
            > </q>
            >
            > Would it be asking too much to try this one again, this time
            including
            > rebounds in the accounting? Common Wisdom has it that 3 pointers
            generate
            > more offensive rebounds, which could add to the value of the long
            attempts.
            > (I'm aware that DeanO disputes CW in his book, and I accept his
            conclusion
            > that 3 misses are no more likely to be offensively rebounded than 2
            misses.
            > Independent confirmation would be very nice, however.)
            >
            > * <quote>
            > Null Hypothesis: steals and turnovers have the same value, but
            opposite
            > signs
            >
            > It is a fairly close call, but the null hypothesis is rejected. It
            appears
            > that steals help teams more than turnovers hurt teams. This could
            be because
            > guys who get steals disrupt offenses in other ways that are not
            picked up in
            > traditional statistics.
            > </q>
            >
            > Is there some double counting going on here? A steal is always a
            turnover,
            > but a turnover is not always a steal. Is it possible to isolate the
            types of
            > turnovers (steals, bad pass, OFF foul, etc.) in this analysis?
            >
            > * <quote>
            > Null Hypothesis: offensive and defensive rebounds have the same
            value
            >
            > There is no evidence to reject this hypothesis. Thus, even though
            these two
            > regressions have higher coefficients for defensive rebounds (versus
            > offensive rebounds), there really is no evidence to conclude
            statistically
            > that the value of defensive rebounds is higher than that of
            offensive
            > rebounds. That said, it is very, very difficult to draw the
            conclusion from
            > these data that offensive rebounds should be valued higher than
            defensive
            > rebounds, as is often argued.
            > </q>
            >
            > Still a topic of great interest for me. My opinion, backed
            tentatively by
            > the data I've looked at, is that defensive rebounds have less
            marginal value
            > than offensive rebounds. That is, an individual player's defensive
            rebound
            > adds less to his team's defensive rebounding percentage than that
            player's
            > offensive rebound adds to his team's offensive rebounding
            percentage. I'm
            > not sure if you address this: it could be that DRebs and ORebs add
            the same
            > amount to a team's production, while at the same time saying each
            _player's_
            > O and D rebounds have a different value.
            >
            >
            >
            >
            > --
            > cheers,
            > ed
          • Mike G
            ... that a ... shot. ... is ... This platitude surely predates the 3-point shot. And the danger in a player getting a rebound may lie more in what he ll do
            Message 5 of 5 , Mar 2 7:27 AM
            • 0 Attachment
              --- In APBR_analysis@yahoogroups.com, "John Hollinger"
              <alleyoop2@y...> wrote:
              > My research in the 2002 Prospectus showed just the opposite --
              that a
              > 3-pointer had LESS chance of being rebounded than a two-point
              shot.
              > Which makes sense, because coaches are fond of saying the most
              > dangerous rebounder is the shooter, and on a 3-pointer the shooter
              is
              > too far away to get most rebounds.

              This platitude surely predates the 3-point shot. And the "danger"
              in a player getting a rebound may lie more in what he'll do with it,
              than in the chances of his getting it.

              So given that a missed 3 is no more likely (or less likely) to be
              rebounded offensively, what accounts for the difference detected by
              Dr. Dan ?

              What about the missed shot that goes out of bounds? Probably more
              likely on a 3 than on a 2. Does the defense get a rebound? No, but
              effectively it's the same. Do they then get a fast break
              opportunity? No.

              So teams that shoot a lot of 3's may have relatively fewer fast
              breaks run against them. Yet they may have relatively more
              offensive rebounds. For both reasons, the outside-shooting team
              gains a cushion against a bigger/stronger opponent.

              This brings up the effect of "difference in team style". For a team
              without inside scoring, it does make sense to shoot more long
              shots. Forcing the ball inside makes the offense less efficient.

              Meanwhile, it's possible for an inside-efficient team to be even
              more efficient when shooting the 3. A mediocre 3-pt shooter can be
              a lot better when he's wide open all day, due to doubling inside.

              Smart coaches and teams take what is given them, most of the time.
              For the past several years (since before the shortened-arc era of
              the mid '90s), 3-pt shooting is (league-wide) more efficient than 2-
              pt and FT combined.




              >
              >
              >
              > --- In APBR_analysis@yahoogroups.com, igor eduardo küpfer
              > <edkupfer@r...> wrote:
              > > From: "dan_t_rosenbaum" <rosenbaum@u...>
              > > * <quote>
              > > Null Hypothesis: the cost of two point FGA is the same as the
              cost
              > of three
              > > point FGA
              > >
              > > The null hypothesis is soundly rejected with three point FGA
              having
              > a lower
              > > cost, even after accounting for points produced and free throw
              > attempts
              > > generated.
              > > </q>
              > >
              > > Would it be asking too much to try this one again, this time
              > including
              > > rebounds in the accounting? Common Wisdom has it that 3 pointers
              > generate
              > > more offensive rebounds, which could add to the value of the
              long
              > attempts.
              > > (I'm aware that DeanO disputes CW in his book, and I accept his
              > conclusion
              > > that 3 misses are no more likely to be offensively rebounded
              than 2
              > misses.
              > > Independent confirmation would be very nice, however.)
            Your message has been successfully submitted and would be delivered to recipients shortly.