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* PROGRAM FOR THE JULY/AUGUST 1997 REVIEW ARTICLE BY DONALD S. ALLEN   *

* "DO INVENTORIES MODERATE FLUCTUATIONS IN OUTPUT?"  PAGES 39 - 50     *

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* NOTE:  COMPUSTAT DATA ARE PROPRIETARY AND THUS ARE NOT AVAILABLE     *

************************************************************************;



libname perm '~/da';

options nocenter ps=59;



**********************************************

** DELETED FROM ORIGINAL DATASET            **

**********************************************

** if sic2 <= 10                            **

** if inv <=0                               **

** if sales <=0                             **

** if any CNUM ending in Z(42 of them)      **

** if dinv=.                                **

** if any CNUM with nonconsecutive quarters **

**    2,112 of them                         **

** if sic2 in(40,41,42,44,45,46,47,48,49,   **

**           60,61,62,63,64,65,67,          **

**           70,72,73,75,76,78,79,          **

**           80,82,83,87,                   **

**           99)                            **

**********************************************;





*****************************

*** ALTERED Compustat DATA  *

*****************************;

DATA G1;SET PERM.ALTINV(WHERE=(DATE GE 81.2 AND DATE LE 91.1));





* >>> Buffer Stock <<< ...;

*********************************

*** UNAGGREGATED by Company   ***

*********************************;



*********************************

* TABLE 2 COLUMN #3 AND #6   ***

* TABLE 1 COLUMN #3          ***

*********************************;

proc corr noprint noprob nosimple data=g1 outp=corout;

  var dinv dsales;

  by sic2 cnum;

 title1;

 title2 'Results of Proc Corr by Sic2 Cnum';

 title3 '   UNAGGREGATED ONLY ';

 title4;



data g3;set corout(keep=dinv _type_ _name_ cnum sic2);

   if _type_='CORR' and _name_= 'DSALES' ;

proc print ;

 title1;

 title2 'SELECTED Correlation output dataset';

 title3 '   UNAGGREAGATED ONLY ';

 title4;



 proc means mean n data=g3;by sic2;

  title1;

  title2 'AVERAGE Correlation Coefficient ';

  title3 'UNAGGREGATED ONLY...81.2 to 91.1 ';

  title4;







*********************************

*** TABLE 2 COLUMN #4         ***

*** AGGREGATED by SIC2 CODE   ***

*********************************;



data a1;set g1;

  proc sort data=a1 out=a2;by sic2 date;

  proc means noprint data=a2;

   var dinv dsales ;

   by sic2 date;

    output out=aa2 sum=;



data a3;set aa2(drop=_type_);

proc print ;

title1;

title2 '  Aggregate(SUM) by Sic2 and Date ';

title3 '  81.2 to 91.1 ;

title4;



proc corr nosimple data=a3 outp=acorout;

  var dinv dsales;

  by sic2 ;

  title1;

  title2 'Proc Corr by Sic2(81.2-91.1)';

  TITLE3 '     AGGREGATED ONLY        ';

  title4;







**********************

*  TABLE 1 COLUMN #4 *

**********************;

* >>> Production Smoothing UNAGGREGATED Firm Level <<< ;

DATA p1;SET PERM.ALTINV(WHERE=(DATE GE 81.2 AND DATE LE 91.1));



  proc sort data=p1 out=p2;by sic2 cnum;

  proc means noprint data=p2;

   var purch sales ;

   by sic2 cnum;

   output out=ap2 var=;

PROC PRINT DATA=AP2;

title1;

title2 'Variance by Sic2 and Cnum ';

title3 '    81.2 to 91.1          ' ;

title4;





data p3;set ap2(drop=_type_);

  vpvsrat=purch/sales;

proc print ;

title1;

title2 '  RATIO(vpvsrat) = Var Purch / Var Sales ';

title3 '  81.2 to 91.1' ;

title4;





**********************

* TABLE 1 COLUMN #6  *

**********************;

* >>> Production Smoothing AGGREGATED <<< ;

DATA P1;SET PERM.ALTINV(WHERE=(DATE GE 81.2 AND DATE LE 91.1));

  proc sort data=p1 out=p2;by sic2 ;





  proc means noprint data=p2;

   var purch sales dinv;

   by sic2 ;

   output out=ap2 var=;

PROC PRINT DATA=AP2;

title1;

title2 '  AGGREGATED Variance Sic2 ';

title3 '  81.2 to 91.1 >>>  Servo > da/IS1A.sas' ;

title4;





data p3;set ap2(drop=_type_);

  vpvsrat=purch/sales;

proc print data=p3;

title1;

title2 '  AGGREGATED RATIO(vpvsrat) = Var Purch / Var Sales ';

title3 '  81.2 to 91.1 ' ;

title4;





**********************

* TABLE 1 COLUMN #7  *

**********************;

** GIVES VARIANCE FOR EACH VARIABLE AND COVARIANCE BETWEEN THEM ;

proc corr nosimple cov data=p2 outp=covout;

  var sales dinv;

  by sic2 ;

 title1;

 title2 'Proc Corr by Sic2 >>> Covariance';

 title3 'AGGREGATED ONLY(81.2-91.1)';

 title4;







*************************************

* TABLE 1 AND TABLE 2 FOR COLUMN #5 *

*************************************;

DATA ALL;SET PERM.ALTINV(WHERE=(DATE GE 81.2 AND DATE LE 91.1));





* >>> Production Smoothing UNAGGREGATED Firm Level<<< ;

data p1;set all;

  proc sort data=p1 out=p2;by SIC2 CNUM;

  proc means noprint data=p2;id sic2 ;

   var purch sales ;

   BY SIC2 CNUM;

   output out=ap2 var=vpurch vsales mean=mpurch msales;



data ap2;set ap2(drop=_type_);

 vpvsrat=vpurch/vsales;





proc print data=ap2;

title1;

title2 '  Variance & Mean by SIC2 and CNUM ';

title3 '  Servo > da/IS1B.SAS(81.2 to 91.1)' ;

title4;





* >>> AGGREGATED(SUM) by Sic2 DATE <<< ;

data p3;set all;

  proc sort data=p3 out=p4;by SIC2 DATE;

 proc means noprint data=p4;

 var sales ;

  * var sales inv dinv;

  *  var sales inv ;

  *BY SIC2 date;

   BY SIC2 cnum;

 output out=ap4 sum=ssales;;

  *output out=ap4 sum=;



 proc means noprint data=ap4;

 var ssales ;

  *var inv sales ;

  BY SIC2 ;

 output out=ap5 mean=xsales n=nsales;

  *output out=ap5 ;

 data ap5;set ap5(drop=_type_ _freq_);

  *data ap5;*set ap5;



proc print noobs data=ap5;

title1;

title2 '  Mean and NOB of SUMMED variables by SIC2 ';

title3;









data g0;set all;

proc sort data=g0 out=g1;by SIC2 CNUM;



* >>> Buffer Stock <<< ...;

*********************************

*** UNAGGREGATED by Company   ***

*********************************;



*** GET COVARIANCE OF SALES DINV *** ;

proc corr cov noprint noprob nosimple data=g1 outp=covout;

  var sales dinv ;

  by sic2 cnum;

 title1;

 title2 'Results of Proc Corr by Sic2 Cnum';

 TITLE3 'COVARIANCE...UNAGGREGATED ONLY(81.2-91.1) ';

 title4;



data cov1;set covout(keep=sales _type_ _name_ cnum sic2);

   if _type_='COV' and _name_= 'DINV' ;







*** GET CORRELATION COEFFIEIENT OF DINV AND DSALES  *** ;

proc corr noprint noprob nosimple data=g1 outp=corout;

  var dinv dsales ;

  by sic2 cnum;

 title1;

 title2 'Results of Proc Corr by Sic2 Cnum';

 title3 '   UNAGGREGATED ONLY(81.2-91.1) ';

 title4;





 proc print DATA=COROUT;

  title1;

  title2 'ENTIRE Correlation output dataset';

  title3 '   UNAGGREGATED ONLY ';

  title4;







data g3;set corout(keep=dinv _type_ _name_ cnum sic2);

   if _type_='CORR' and _name_= 'DSALES' ;







proc print ;

 title1;

 title2 'SELECTED Correlation output dataset';

 title3 '   UNAGGREAGATED ONLY ';

 title4;





 proc means mean n data=g3;by sic2;

  title1;

  title2 'AVERAGE Correlation Coefficient ';

  title3 '   UNAGGREGATED ONLY ';

  title4;









*****************************

** WEIGHTING OF VARIABLES  **

*****************************;



data b1;merge ap2 g3 cov1 ap5;by sic2;

wght= (_freq_ / nsales) * (msales/xsales);* firm sales / total sales;

  wvpvsrat=wght*vpvsrat;

  wdinv=wght*dinv;* correlation coefficient between dinv and dsales.;

  wsales=wght*sales;* covariance between sales annd dinv..;





proc print data=b1;

title1;

title2 ' Mean Sales of individual companies and TOTAL for sic2 ';

title3;





  proc means sum data=b1;by sic2;

   var wght wvpvsrat wdinv wsales;

title1;

TITLE2 '  WEIGHTED SUM OF WGHT, VPVSRAT ...and...';

TITLE3 '  CORR COEF(dinv dsales) COV(sales div)..';

TITLE4 '            81.2 to 91.1';

title5;



run;