topic Re: Create visit variable in SAS Programming

Create visit variable

rfarmenta — Wed, 08 Jul 2015 15:27:18 GMT

I have a long dataset that includes multiple records per participant. Each person has an overall date range (begin_date and end_date) for trips they have made to conduct business for their job. Additionally, each person has a date1 and a dot1 that indicated shorter duration trips that fall within their overall begin_date and end_date. What I need is a new variable that gives a trip number for each row of the data. So for example, in the small dataset below for participant 1, row 1 would be trip 1, so my new variable trip, would be equal to 1, rows 2-5 are trip 2 and there were 4 shorter trips associated with trip 2, then rows 6-9 are trip 3 and they were 4 shorter trips associated with the overall date range. You can tell if the date1 and dot1 dates are all within a larger trip if the dates fall within begin_date and end_date. So basically I want to add a variable called trip and for the example row 1 would be 1, rows 2-5 would be 2, and rows 6-9 would be 3.

I tried using the following code but it just gives me a count of all the rows essentially. I think the code doesn't work because I have repeated measures and it is hard to distinguish between dates but I was hoping to be able to do this without transforming the data. Any help would be greatly appreciated.

data want;

set have;

trip+1;

by begin_date;

if first.begin_date then trip=1;

else if date1>end_date and dot1<=end_date then trip=trip+1;

run;

ID	begin_date	end_date	date1	dot1
1	02/12/06	04/29/06	02/12/06	04/29/16
1	03/14/07	01/15/08	03/14/07	04/18/07
1	03/14/07	01/15/08	04/18/07	05/16/07
1	03/14/07	01/15/08	05/16/07	09/02/07
1	03/14/07	01/15/08	09/02/07	01//15/08
1	05/15/10	08/05/12	06/26/10	08/15/10
1	05/15/10	08/05/12	01/20/11	01/25/11
1	05/15/10	08/05/12	02/01/11	08/01/11
1	05/15/10	08/05/12	04/01/12	04/03/12

Re: Create visit variable

Steelers_In_DC — Wed, 08 Jul 2015 16:00:59 GMT

Here you go, let me know if I missed a step:

data have;

infile cards dsd;

informat ID $1. begin_date end_date date1 dot1 mmddyy8.;

format ID $1. begin_date end_date date1 dot1 mmddyy8.;

input ID begin_date end_date date1 dot1;

cards;

1,02/12/06,04/29/06,02/12/06,04/29/16

1,03/14/07,01/15/08,03/14/07,04/18/07

1,03/14/07,01/15/08,04/18/07,05/16/07

1,03/14/07,01/15/08,05/16/07,09/02/07

1,03/14/07,01/15/08,09/02/07,01/15/08

1,05/15/10,08/05/12,06/26/10,08/15/10

1,05/15/10,08/05/12,01/20/11,01/25/11

1,05/15/10,08/05/12,02/01/11,08/01/11

1,05/15/10,08/05/12,04/01/12,04/03/12

;

data want;

set have;

by id begin_date;

if first.begin_date then trip + 1;

run;

Re: Create visit variable

ballardw — Wed, 08 Jul 2015 16:19:35 GMT

May want to modify Mark's code with a reset for each ID if the idea is to have trips per Id.

by id begin_date;

if first.id then trip=0; /* reset for each id*/

if first.begin_date then trip + 1;

run;

Re: Create visit variable

rfarmenta — Wed, 08 Jul 2015 16:57:56 GMT

That was much simpler than I thought, thank you both for your input, the code worked.