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Re: [APBR_analysis] Times Fouled and Possessions

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  • 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 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.

      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 2 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 3 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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