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Times Fouled and Possessions

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  • bricks299
    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 1 of 8 , Jun 22, 2003
      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.

      This figure is easily derived using the following 2001-02 NBA team
      averages...

      Free Throw Attempts (FTA) = 1953
      Technical Foul Free Throw Attempts (TFTA) = 82
      Good plus Foul Shooting Opportunities (GF) = 160

      Adjusted Free Throw Attempts will be used since TFTA have no relation
      to shooting fouls = 1953 - 82 = 1871

      This formula gives Times Fouled Shooting (TFS) = (AFTA - GF / 2) + GF
      = (1871 - 160 / 2) + 160 = (1711 / 2) + 160 = 855.5 + 160 = 1015.5

      The factor used to estimate TFS = 1015.5 / 1871 = .543

      Since when estimating possessions, GF possessions are included in
      Field Goal Attempts, the formula is adjusted to exclude GF.

      The new factor = 855.5 / 1871 = .457

      Therefore, the correct formula to estimate possessions = FGA + (AFTA)
      (.457) + TO - OReb

      GF may be estimated by subtracting (TFS)(2) from AFTA.

      Ben Ricks
    • bchaikin@aol.com
      could you please run the numbers for say the 97-98 season for each team and list poss/48min game for each team (both off and def poss)? thanks... bob chaikin
      Message 2 of 8 , Jun 22, 2003

        could you please run the numbers for say the 97-98 season for each team and list poss/48min game for each team (both off and def poss)? thanks...

        bob chaikin
        bchaikin@...
      • bricks299
        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
        Message 3 of 8 , Jun 22, 2003
          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:

          1997-98 OFF DEF Diff
          Chicago 91.5 91.2 +0.3
          Indiana 89.5 90.0 -0.5
          Miami 89.8 90.0 -0.2
          Charlotte 91.6 91.6 0.0
          Atlanta 89.6 89.9 -0.3
          Cleveland 91.7 92.1 -0.4
          New Jersey 93.5 93.4 +0.1
          New York 89.9 90.4 -0.5
          Washington 93.9 93.8 +0.1
          Orlando 90.1 88.9 +1.2
          Detroit 90.8 90.1 +0.7
          Boston 95.7 94.9 +0.8
          Milwaukee 92.1 92.4 -0.3
          Philadelphia 92.5 92.2 +0.3
          Toronto 94.7 95.0 -0.3

          Utah 91.6 91.4 +0.2
          Seattle 91.9 91.5 +0.4
          Los Angeles-L 95.6 95.6 0.0
          Phoenix 93.4 93.5 -0.1
          San Antonio 89.8 90.6 -0.8
          Portland 92.3 92.3 0.0
          Minnesota 94.9 95.1 -0.2
          Houston 93.3 93.1 +0.2
          Sacramento 94.2 94.2 0.0
          Dallas 91.8 91.7 +0.1
          Vancouver 94.2 93.7 +0.5
          Golden State 93.7 93.6 +0.1
          Los Angeles-C 94.6 94.5 +0.1
          Denver 91.6 91.7 -0.1

          The biggest difference is +/- 0.8 possessions per 48 minutes.

          Ben Ricks

          --- In APBR_analysis@yahoogroups.com, bchaikin@a... wrote:
          >
          > could you please run the numbers for say the 97-98 season for each
          team and
          > list poss/48min game for each team (both off and def poss)?
          thanks...
          >
          > bob chaikin
          > bchaikin@b...
        • igor eduardo küpfer
          ... From: bricks299 To: Sent: Sunday, June 22, 2003 1:45 PM Subject: [APBR_analysis] Re: Times
          Message 4 of 8 , Jun 22, 2003
            ----- 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 5 of 8 , Jun 22, 2003
              --- 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 6 of 8 , Jun 22, 2003
                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 7 of 8 , Jun 22, 2003
                  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 8 of 8 , Jun 23, 2003
                    --- 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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