topic creating a new variable based on a frequency in SAS Procedures

creating a new variable based on a frequency

c_starfish — Sun, 01 Oct 2017 17:41:35 GMT

Hello,

I am dealing with data where I have subject IDs and a variable that tells me the diseases each subject has. Some of the subjects have more than one disease but they are just inputted in the dataset multiple times. For example:

data example;

input ID condition$ ;

datalines;

45 diabetes

46 cancer

46 diabetes

47 cancer

;

What I want is a summary of the frequency of conditions. For example, X number of people have only one condition but Y number of people have two conditions and Z number of people have three conditions, etc. I am thinking that I would just like to create a variable that tells me the number of conditions each participant has but I am not sure how to do this.

Is there a way I can do this?

Re: creating a new variable based on a frequency

Reeza — Sun, 01 Oct 2017 18:01:56 GMT

Is a patient going to have multiple diagnosis entries for the same event, ie will diabetes be there twice?

If not, you can use a PROC FREQ to get the number of counts. Otherwise, you're looking to count distinct.

I just posted a solution on how to count distinct items per group here:

https://communities.sas.com/t5/SAS-Statistical-Procedures/Count-unique-variables-associated-with-one-firm/m-p/400084

Re: creating a new variable based on a frequency

error_prone — Sun, 01 Oct 2017 18:02:20 GMT

Use proc summary to get the number of conditions each patient has, then pro freq to get the required output.

proc summary data=example nway;
   class id;
   output out=CondById(drop=_type_ rename=(_freq_=NumConditions));
run;


proc freq data=CondById noprint;
   tables NumConditions / out=FreqCond(drop=percent);
run;

Re: creating a new variable based on a frequency

c_starfish — Sun, 01 Oct 2017 18:40:21 GMT

Hey thank you so much! what an easy solution to my problem. You rock!