*---------------------------------------------------------------*
| Program Name: HILOWPER.SAS  in C:\CLEANING                    |
| Purpose: To list the n percent highest and lowest values for  |
|          a selected variable.                                 |
| Arguments: DSN    - Data set name                             |
|            VAR     - Numeric variable to test                 |
|            PERCENT - Upper and Lower percentile cutoff        |
|            IDVAR   - ID variable to print in the report       |
| Example: %HILOWPER(CLEAN.PATIENTS,SBP,20,PATNO)               |
*---------------------------------------------------------------*;
%MACRO HILOWPER(DSN,VAR,PERCENT,IDVAR);

   ***Compute upper percentile cutoff;
   %LET UP_PER = %EVAL(100 - &PERCENT);

   PROC UNIVARIATE DATA=&DSN NOPRINT;
      VAR &VAR;
      ID &IDVAR;
      OUTPUT OUT=TMP PCTLPTS=&PERCENT &UP_PER PCTLPRE = L_;
   RUN;

   DATA HILO;
      SET &DSN(KEEP=&IDVAR &VAR);
      IF _N_ = 1 THEN SET TMP;
      IF &VAR LE L_&PERCENT THEN DO;
         RANGE = 'LOW ';
         OUTPUT;
      END;
      ELSE IF &VAR GE L_&UP_PER THEN DO;
         RANGE = 'HIGH';
         OUTPUT;
      END;
   RUN;

   PROC SORT DATA=HILO(WHERE=(&VAR NE .));
      BY DESCENDING RANGE &VAR;
   RUN;

   PROC PRINT DATA=HILO;
      TITLE "Low And High Values For Variables";
      ID &IDVAR;
      VAR RANGE &VAR;
   RUN;

   PROC DATASETS LIBRARY=WORK NOLIST;
     DELETE TMP;
     DELETE HILO;
   RUN;
   QUIT;

%MEND HILOWPER ;