topic Re: create composite variable in SAS Programming

create composite variable

grayskillen — Wed, 20 Jan 2016 21:27:04 GMT

I have a dataset related to kidney transplants and each donor has a donor id and both the left and right kidneys are tied to that donor id.

I need to create a binary variable called 'discard' (0=no, 1=yes) that is a composite of left and right kidney dispositions.

Currently I have the variables:

donor_id

r_disp (5=discard, 6=transplant)

l_disp (5=discard, 6=transplant)

How do I create a variable called "discard" that will be a composite indicator of r_disp and l_disp so that I can investigate the odds of discard overall?

Re: create composite variable

ballardw — Wed, 20 Jan 2016 21:34:31 GMT

If r_disp and l_disp are on the same record in a data step:

(flag if either are discarded)

discard = (r_disp=5 or l_disp=5);

(flag if BOTH are discarded)

discard = (r_disp=5 and l_disp=5);

Re: create composite variable

mohamed_zaki — Wed, 20 Jan 2016 21:36:55 GMT

Could you give example of the data you have ?

Re: create composite variable

grayskillen — Wed, 20 Jan 2016 21:55:31 GMT

A single observation will show data for the following variables (among others):

Donor_id
r_disp (fate of right kidney)
L_disp (fate of left kidney)
Kdri (measure of kidney quality)

Donor_id is the index variable.

I want to run a proc logistic to investigate the odds of discard but I only have discard data by left and right. So I need to combine them someone into one discard variable for analysis.

Re: create composite variable

mohamed_zaki — Wed, 20 Jan 2016 21:58:00 GMT

Yes, what your logic ?

if both of them are diecard then discard =1

if any one of them is dicard then discard=1

Re: create composite variable

mohamed_zaki — Wed, 20 Jan 2016 22:01:11 GMT


data have ;
input ID r_disp l_disp;
cards;
111 5 5
112 6 6
113 5 6
114 6 6
;
run;

data want ;
set have;
if r_disp=5 and l_disp=5 then discard=1;
else discard =0;
run;

That is example.

If you want discard to equal 1 if the right or the left is discard then change the "and" to "or" in the IF condition.

Re: create composite variable

Steelers_In_DC — Thu, 21 Jan 2016 15:55:15 GMT

The logic of discard or not isn't clear but something like this seems right:

data have;
input ID$ r_disp$ l_disp$;
cards;
1 5 5
2 5 6
3 6 5
4 6 6
;run;

data want;
set have;
if r_disp = '6' or l_disp = '6' then Discard = '0';
else discard = '1';
run;