topic Re: Checking How Many Participants have a certain number of visits in Statistical Procedures

Checking How Many Participants have a certain number of visits

zaldarsa — Sat, 19 Feb 2022 09:38:44 GMT

Hi!

I want see how many individuals in my data set have visits 1-7, how many have visits 1-8, and how many have visits 1-9. What would be an efficient way to go about doing this? Thank you all in advance for your help.

Re: Checking How Many Participants have a certain number of visits

PaigeMiller — Sat, 19 Feb 2022 11:04:06 GMT

Can you show us a portion of your data so we can understand what the data looks like?

Re: Checking How Many Participants have a certain number of visits

zaldarsa — Sat, 19 Feb 2022 17:33:12 GMT

Sure. So here is an example of what my data looks like, except my dataset has around 400 observations.

ID       Visit
1            1
1            2
1            3
2            1
3            1
3            2
3            3
3            4
3            5
3            6
3            7
4            1
4            2
4            3
5            1
5            2
5            3
5           4
5           5
5           6
5           7
5           8
6            1
6           2
6           3
6           4
6           5
6           6
6           7
6          8
6           9

Re: Checking How Many Participants have a certain number of visits

Reeza — Sat, 19 Feb 2022 17:57:41 GMT

Assuming your data is always consecutive you only need the last for each ID really.

*get maximum per ID;
proc sql;
create table id_max as
select id, max(visit) as max_visit from have;
quit;

*check distribution;
proc freq data=id_max;
table max_visit;
run;

@zaldarsa wrote:

Sure. So here is an example of what my data looks like, except my dataset has around 400 observations.

ID       Visit
1            1
1            2
1            3
2            1
3            1
3            2
3            3
3            4
3            5
3            6
3            7
4            1
4            2
4            3
5            1
5            2
5            3
5           4
5           5
5           6
5           7
5           8
6            1
6           2
6           3
6           4
6           5
6           6
6           7
6          8
6           9

Re: Checking How Many Participants have a certain number of visits

PaigeMiller — Sat, 19 Feb 2022 20:19:41 GMT

So is it valid to assume that the numbers in the VISIT column are always consecutive within an ID? That the numbers in the VISIT column never repeat or skip?

Re: Checking How Many Participants have a certain number of visits

zaldarsa — Sat, 19 Feb 2022 20:53:34 GMT

They are in order, but i didn't double check my data, and it does indeed skip, but no repeat. For example, visit 3 may not be there for some people.

Re: Checking How Many Participants have a certain number of visits

PaigeMiller — Sat, 19 Feb 2022 21:01:28 GMT

Well don't leave us in suspense. What happens to an ID that doesn't have Visit 3 but has 1, 2, 4, 5, 6? Is that the 1-6 category? Or do you want it to be categorized some other way?

Re: Checking How Many Participants have a certain number of visits

zaldarsa — Sat, 19 Feb 2022 21:36:04 GMT

I apologize for my lack of clarity. It would still be visit 1-6 regardless of what is missing in between, so I would still apply a similar code as if it were consecutive , in that case, correct?

Re: Checking How Many Participants have a certain number of visits

PaigeMiller — Sat, 19 Feb 2022 21:43:13 GMT

proc summary data=have nway;
    class id;
    var visit;
    output out=stats max=max_visit;
run;