Friday, May 27, 2011

True Distribution Analysis with 2-Point FG replacing All FG

As suspected, replacing the field goal data with two-point field goal data found a stronger relationship between the standard deviation of the percentage of two-point field goal attempts taken by each player in the lineup and the lineup OPPP than was found between the standard deviation of the percentage of all field goal attempts taken by each player in the lineup and the lineup OPPP. 




This graph illustrates that increasing the standard deviation of the percentage of two-point field goals attempted by each of the players in a lineup can increase the lineup OPPP by as much as 3 points per 100 possessions, more than found with respect to field goal attempts generally.  


Interestingly, the coefficient for the standard deviation of the percentage of two-point field goals attempts with respect to the dependent variable of lineup two-point field goals made per possession was negative, while it was positive with respect to the dependent variables of lineup three-point field goals made per possession and lineup free throws made per possession.  This indicates that while a greater distribution of two-point field goal attempts predicts a greater number of three-point field goals made per possession and to a lesser extent a greater number  of free throws made per possession, it also predicts fewer two-point field goals made per possession.  

4 comments:

  1. Good work, Nima!

    Could you report r^2 values, please? It would help the reader understand the strength of the correlation. Thanks!

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  2. Daniel, thank you for your feedback.

    When using lineup data, the r^2 in predicting OPPP 2PFGM/poss, FTM/poss and 3PM/poss is 1.000, as is probably obvious to you since Points = 2*2PFGM + 3*3PM + FTM.

    The r^2's for 2PFGM/poss, 3PM/poss and FTM/poss as predicted by the significant standard deviation variables are, .080, .166 and .079, respectively.

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  3. That's rather low--is the slope significant when running the regression?

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  4. In predicting 2PFGM/poss, the 5 variables with t-values with absolute value over 1.4 were the standard deviations of the % of 2PFGA, 3PA, OREB, AST and TO and the sig values were, .000, .000, .000, .060, and .152, respectively.

    In predicting 3PM/poss, the 5 variables with t-values with absolute value over 1.4 were the standard deviations of the % of 2PFGA, 3PA, FTA, OREB, and TO and the sig values were, .000, .025, .000, .003, and .036, respectively.


    In predicting FTM/poss, the 4 variables with t-values with absolute value over 1.4, were the standard deviations of the % of 2PFGA, 3PA, FTA and TO and the sig values were, .000, .101, .000, and .050, respectively.

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