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Re: My Version 2 of WINVAL

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  • 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 1 of 5 , Mar 1, 2004
      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 2 of 5 , Mar 2, 2004
        --- 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.)
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