topic Pre- Test and Post- Test Data in SAS Programming

Pre- Test and Post- Test Data

Denali — Mon, 02 Oct 2017 14:51:39 GMT

I have 70 variables are pre-test and another 70 variables are post-test. I am going to do the two-sample Wilcoxon test., but how do I format these variable so I will have a new variable called "time" that tells SAS the timepoint: pre=1 and post=2 for each pair?

70 Pre-test variables:

PRETC1

PRETC2

PRETC3

PRETC4

PRETC5

PRETC6

PRETC7

PREEBC1

PREEBC2

PREEBC3

PREEBC4

PREEBC5

PREEBC6

PREEBC7

PREEBC8

PREEBC9

PREEBC10

PREEBC11

PRETOP1

PRETOP2

PRETOP3

PRETOP4

PRETOP5

PRETOP6

PRETOP7

PRETOP8

PRETOP9

PRETOP10

PRETOP11

PRETOP12

PRETOP13

PRETOP14

PRETOP15

PRETOP16

PRETOP17

PRETOP18

PRETOP19

PRETOP20

PRETOP21

PREMENT

PREMENTRANK1

PREMENTRANK2

PREMENTRANK3

PREMENTRANK4

PREMENTRANK5

PREMENTRANK6

PREMENTRANK7

PREMENTRANK8

PREMENTRANK9

PREMENTRANK10

PREMENTRANK11

PREMENTRANK12

PREMENTRANK13

PREMENTRANK14

PREMENTRANK15

PREMENTRANK16

PREMENTRANK17

PREMENTRANK18

PREMENTRANK18SPECIFY

PREMENTRANK19

70 Post-test variables:

POSTTC1

POSTTC2

POSTTC3

POSTTC4

POSTTC5

POSTTC6

POSTTC7

POSTEBC1

POSTEBC2

POSTEBC3

POSTEBC4

POSTEBC5

POSTEBC6

POSTEBC7

POSTEBC8

POSTEBC9

POSTEBC10

POSTEBC11

POSTTOP1

POSTTOP2

POSTTOP3

POSTTOP4

POSTTOP5

POSTTOP6

POSTTOP7

POSTTOP8

POSTTOP9

POSTTOP10

POSTTOP11

POSTTOP12

POSTTOP13

POSTTOP14

POSTTOP15

POSTTOP16

POSTTOP17

POSTTOP18

POSTTOP19

POSTTOP20

POSTTOP21

POSTMENT

POSTMENTRANK1

POSTMENTRANK2

POSTMENTRANK3

POSTMENTRANK4

POSTMENTRANK5

POSTMENTRANK6

POSTMENTRANK7

POSTMENTRANK8

POSTMENTRANK9

POSTMENTRANK10

POSTMENTRANK11

POSTMENTRANK12

POSTMENTRANK13

POSTMENTRANK14

POSTMENTRANK15

POSTMENTRANK16

POSTMENTRANK17

POSTMENTRANK18

POSTMENTRANK18SPECIFY

POSTMENTRANK19

Re: Pre- Test and Post- Test Data

ballardw — Mon, 02 Oct 2017 20:29:53 GMT

You may find reformatting the data to

When C1 C2 C3 ... EBC1 EBC2 EBC3 ...Top1 Top2 Top3 ...

where the first variable indicates Pre Or Post, such as 1 for Pre and 2 for Post.

Then your test would look like:

proc npar1way data=have wilcoxon correct=no data=React;
   class When;
   var C1;
   exact wilcoxon;
run;

Re: Pre- Test and Post- Test Data

Denali — Mon, 02 Oct 2017 21:39:14 GMT

Yes, I understand that I need a variable indicating the timepoint (pre or post). But I don't know how to reformat the data. Should I use transpose or anything?

Re: Pre- Test and Post- Test Data

ballardw — Tue, 03 Oct 2017 15:57:00 GMT

@Denali wrote:

Yes, I understand that I need a variable indicating the timepoint (pre or post). But I don't know how to reformat the data. Should I use transpose or anything?

This is one way to transpose the data:

data want;
   set have;
   When = 1;
   C1=PRETC1; 
   C2=PRETC2; 
   C3=PRETC3; 
   C4=PRETC4; 
   C5=PRETC5; 
   C6=PRETC6; 
   C7=PRETC7; 
   /*all the other PRE variables go here*/
   output; 
   When = 2;
   C1=POSTTC1; 
   C2=POSTTC2; 
   C3=POSTTC3; 
   C4=POSTTC4; 
   C5=POSTTC5; 
   C6=POSTTC6; 
   C7=POSTTC7; 
   /*all the other POST variables go here*/
   output;

   keep when C1 - C7  /*and the other new variables from the left of the = signs*/
run;

Careful use of arrays would shorten the code but I'll leave that as an exercise for the interested reader. Doing something like this by hand is good incentive to learn arrays.