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Re: [APBR_analysis] Re: Times Fouled and Possessions

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  • igor eduardo küpfer
    ... From: bricks299 To: Sent: Sunday, June 22, 2003 1:45 PM Subject: [APBR_analysis] Re: Times
    Message 1 of 8 , Jun 22, 2003
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      ----- Original Message -----
      From: "bricks299" <homecourtgames@...>
      To: <APBR_analysis@yahoogroups.com>
      Sent: Sunday, June 22, 2003 1:45 PM
      Subject: [APBR_analysis] Re: Times Fouled and Possessions


      > Bob
      >
      > I don't have each team's technical FTA. Here are possessions per 48
      > minutes without team rebounds using FGA + (AFTA)(.457) + TO - OReb.
      > Team rebounds are normally close anyway:
      >

      <snip>

      The following is a comparison of the two FTA coefficients (.4 vs .457), as
      shown by the differences between offensive possessions and defensive
      possessions,by season. The smaller coefficient outperforms the larger
      exactly half the time, although with a larger standard error. The difference
      is small enough (to me) as to not warrant using the extra decimal places.
      What is needed is some empirical data, counting actual possessions in a
      game, and seeing how close we are.

      TrimMean SEMean
      .4 .457 .4 .457

      1974 -.037 -.044 .180 .194
      1975 +.055 +.043 .162 .151
      1976 +.702 +.693 .381 .371
      1977 -.006 -.008 .133 .117
      1978 +.072 +.102 .164 .145
      1979 -.031 -.015 .096 .084
      1980 -.158 -.167 .171 .197
      1981 +.045 +.025 .153 .153
      1982 -.016 -.013 .128 .119
      1983 -.016 -.007 .145 .122
      1984 -.005 -.001 .118 .120
      1985 -.005 -.005 .217 .208
      1986 -.009 +.004 .089 .082
      1987 +.012 +.015 .096 .084
      1988 +.004 +.019 .158 .134
      1989 +.011 -.005 .113 .095
      1990 -.013 -.013 .118 .102
      1991 -.057 -.025 .159 .152
      1992 +.061 +.064 .181 .169
      1993 -.032 -.040 .090 .069
      1994 -.090 -.080 .316 .305
      1995 -.006 -.012 .106 .103
      1996 -.003 -.003 .086 .081
      1997 +.012 +.021 .085 .081
      1998 -.008 -.003 .097 .084
      1999 +.017 +.013 .162 .167


      ed
    • Dean Oliver
      ... vs .457), as ... larger ... difference ... places. ... in a ... I ve got some of these. I ll try to pass them on after I m done traveling (again). My
      Message 2 of 8 , Jun 22, 2003
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        --- In APBR_analysis@yahoogroups.com, igor eduardo küpfer
        <igorkupfer@r...> wrote:
        > <snip>
        >
        > The following is a comparison of the two FTA coefficients (.4
        vs .457), as
        > shown by the differences between offensive possessions and defensive
        > possessions,by season. The smaller coefficient outperforms the
        larger
        > exactly half the time, although with a larger standard error. The
        difference
        > is small enough (to me) as to not warrant using the extra decimal
        places.
        > What is needed is some empirical data, counting actual possessions
        in a
        > game, and seeing how close we are.

        I've got some of these. I'll try to pass them on after I'm done
        traveling (again).

        My general comment to Ben when he first passed on his note to me was
        that he may be right that 0.45 works better to account for FT
        possessions. However, there are minor errors in the rest of the
        possession formula associated with team ORs and other little things
        that get lumped into that multiplier on FTA. Or you can get more
        complex with your possession formula, something BobC has done.

        I share the sentiment that it doesn't matter too much. Soon, we will
        be able to just count possessions for each team and do the simple
        division to get pts/poss. Still, the formula estimate will remain
        useful (in historical work, in individual possession calcs), but the
        difference between 0.4 and 0.45 won't make a huge difference in
        estimates. Plus, the multiplier changes with rules and enforcement
        of such. It was lower in the 3-to-make-2 era, for example, and is
        higher in the 1-and-1 world of college hoops.

        DeanO
      • bchaikin@aol.com
        I have noticed that many people have used the following formula to estimate possessions: FGA + (FTA)(.4) + TO - OReb The times fouled shooting factor should be
        Message 3 of 8 , Jun 22, 2003
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          I have noticed that many people have used the following formula to
          estimate possessions:

          FGA + (FTA)(.4) + TO - OReb

          The times fouled shooting factor should be .457; not .4.

          Or you can get more complex with your possession formula, something BobC has done. 

          the proper formula is:

          FGA + FTA/2 + TO - oreb - techFTA - (AOSF FGM) - flagrants

          (denominator 2 larger prior to 81-82 when 3 to make 2 bonus was in affect), but i add 0.33 to account for the techs and flagrants...

          and not more complex, just more exact, simply because it works in a simulation, which does not take into account technicals and flagrants, but does account for AOSF FGM (act of shooting fouls FGM, i.e. traditional 3 pt plays)...

          your average for 97-98 (the last year i updated the sim) was 92.4 poss/48 min/team. the sim uses 91.5 on average and the stats come out pretty much exact (i.e. avg pts/g/team right on the money, well within 1%)....

          if you ever run the B-BALL sim for a full season (takes about 40 seconds on a pentium to run an 1189 game season) it lists each team's poss/g in the final stats file...

          bob chaikin
          bchaikin@...
        • John Hollinger
          I agree with the general sentiment -- if 0.4 vs. 0.44 would only change the result between two players are teams with microscopic differences. Also, in the
          Message 4 of 8 , Jun 22, 2003
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            I agree with the general sentiment -- if 0.4 vs. 0.44 would only
            change the result between two players are teams with microscopic
            differences.

            Also, in the specific example that brought up this thread, there's a
            couple things missing -- times fouled on 3-pointers, flagrant fouls
            and breakaway fouls -- that would further adjust the coefficient.



            --- In APBR_analysis@yahoogroups.com, "Dean Oliver" <deano@r...>
            wrote:
            > --- In APBR_analysis@yahoogroups.com, igor eduardo küpfer
            > <igorkupfer@r...> wrote:
            > > <snip>
            > >
            > > The following is a comparison of the two FTA coefficients (.4
            > vs .457), as
            > > shown by the differences between offensive possessions and
            defensive
            > > possessions,by season. The smaller coefficient outperforms the
            > larger
            > > exactly half the time, although with a larger standard error. The
            > difference
            > > is small enough (to me) as to not warrant using the extra decimal
            > places.
            > > What is needed is some empirical data, counting actual
            possessions
            > in a
            > > game, and seeing how close we are.
            >
            > I've got some of these. I'll try to pass them on after I'm done
            > traveling (again).
            >
            > My general comment to Ben when he first passed on his note to me
            was
            > that he may be right that 0.45 works better to account for FT
            > possessions. However, there are minor errors in the rest of the
            > possession formula associated with team ORs and other little things
            > that get lumped into that multiplier on FTA. Or you can get more
            > complex with your possession formula, something BobC has done.
            >
            > I share the sentiment that it doesn't matter too much. Soon, we
            will
            > be able to just count possessions for each team and do the simple
            > division to get pts/poss. Still, the formula estimate will remain
            > useful (in historical work, in individual possession calcs), but
            the
            > difference between 0.4 and 0.45 won't make a huge difference in
            > estimates. Plus, the multiplier changes with rules and enforcement
            > of such. It was lower in the 3-to-make-2 era, for example, and is
            > higher in the 1-and-1 world of college hoops.
            >
            > DeanO
          • Dean Oliver
            ... affect), ... The problem is that your last 3 terms aren t available in most stat books so we end up estimating them. I just end up rolling them into the
            Message 5 of 8 , Jun 23, 2003
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              --- In APBR_analysis@yahoogroups.com, bchaikin@a... wrote:
              > the proper formula is:
              >
              > FGA + FTA/2 + TO - oreb - techFTA - (AOSF FGM) - flagrants
              >
              > (denominator 2 larger prior to 81-82 when 3 to make 2 bonus was in
              affect),
              > but i add 0.33 to account for the techs and flagrants...
              >

              The problem is that your last 3 terms aren't available in most stat
              books so we end up estimating them. I just end up rolling them into
              the multiplier on FTA, but there are other ways.

              DeanO
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