counting process for time-dependent covariate

[Merdock]

I have the following dataset:

data have;
input ID$ TRANSDATE:mmddyy. CENSDATE:mmddyy. FUTIME CENSOR SWITCHTIME GROUP$;
format TRANSDATE mmddyy10. CENSDATE mmddyy10.;
datalines;
001	7/2/2002	7/11/2003	344	1	344	1
002	8/23/2001	7/30/2002	311	0	311	1
003	3/27/2002	10/1/2007	1984	1	1984	1
004	1/28/2000	3/26/2011	4045	1	0	2
005	8/6/2002	12/16/2005	1198	0	1198	1
006	1/23/2001	9/8/2005	1659	0	12	3
007	4/10/2003	3/10/2006	1035	0	1035	1
008	8/26/2002	3/26/2008	2009	0	2009	1
009	8/14/2014	9/15/2016	733	0	18	3
010	11/3/2000	11/10/2003	1072	0	1072	1
011	4/11/2001	9/12/2007	2315	0	2315	1
012	2/5/2002	1/2/2006	1397	0	1397	1
013	7/11/2000	1/2/2008	2701	0	0	2
014	5/7/2002	11/10/2008	2349	0	2349	1
015	9/23/2001	2/7/2005	1203	0	6	3
;
run;
proc print data=have; run;

How can I get this dataset into a counting process format for time-dependent covariate survival analysis? The time-dependent covariate would be “switch” from table below. The IDs whose FUTIME NE SWITCHTIME (group=3) are the ones who switched from group 1 to group 2 at that respective SWITCHTIME so they would get switch=1. I also want everybody who had SWITCHTIME=0 to have switch=1.

I’ve already done this in R but I want to double check my results in SAS and also learn how to convert this dataset using data steps, as opposed to programming statement.

So basically I want my final dataset to look like this:

Thanks!

[ballardw · Accepted solution]

Where do the values of  Tstart, Tstop and status come from??? Your want also shows two values of Id=006. Why?

If you have accurately described how Switch is to be set then maybe:

data switch;
   set have;
   switch= ( (FUTIME NE SWITCHTIME) or  (SWITCHTIME=0) );
run;

But you appear to be missing a number of details.

[Merdock]

Thanks so much and my apologies for the delayed response, a lot going on the past month!