Help with PROC FORMAT

[amng]

Hi, I've recently downloaded a public data set for analysis, and they have some data in MMYYYY format. I would like to be able to use this data to understand the number of people that have received a service in the last 12 months. I think I need SAS to recognize the six numbers as a date, but am unsure how to do that.

It seems like I'll have to use proc format to create a format to do that - I've scoured the other message boards, but haven't found the exact answer to my problem.

Help appreciated!

[PaigeMiller]

Is the variable that contains MMYYYY character or numeric?

You won't need PROC FORMAT, but I do need answer to the above question to know how to proceed.

[amng]

Thanks for responding! The variable is numeric.

[PaigeMiller · Accepted solution]

Create a new variable that is an actual SAS date value. Then finding out how long it has been since the last service is easy mathematically. 

data want;
    set have;
    sasdate=input(put(date,6.),yymmn6.);
    format sasdate date7.;
run;

Then you could subtract this date from the date of the last  service, if the number is > 365, then no service in the last 12 months.

[amng]

Thanks! This was really helpful.

[unison]

Adding onto @PaigeMiller 's response: you can take advantage of the INTNX function for the last part to avoid any issues with leap-years, etc. Assuming today is the comparison date for "within the last 12 months" and no future observations:

if intnx("month",sasdate,12,"s") ge today();

 or

if intnx("year",sasdate,1,"s") ge today();

Bringing the service date of the observation forward 12 months (or 1 year), is it greater than or equal to today's date?