topic Re: Selecting timepoints in longitudinal data in New SAS User

Selecting timepoints in longitudinal data

Stanley3 — Thu, 18 Jul 2024 16:38:27 GMT

Hi,

I have a dataset with multiple timepoint measurements for the same ID. For each unique ID, I need to keep only the earliest observation and delete the rest. How can I code this?

Additionally, using the example below, how can I fill in the missing value for the 'sex' variable at timepoint 1 with the value from timepoint 2?

Thank you!

ID	Timepoint	Sex
0001	1
0001	2	Female
0001	3	Female
0002	2	Male
0002	3	Male
0003	2	Male
0003	4	Male

Re: Selecting timepoints in longitudinal data

PaigeMiller — Thu, 18 Jul 2024 16:48:48 GMT

@Stanley3 wrote:

I have a dataset with multiple timepoint measurements for the same ID. For each unique ID, I need to keep only the earliest observation and delete the rest. How can I code this?

data want;
    set have;
    by id;
    if first.id;
run;

Additionally, using the example below, how can I fill in the missing value for the 'sex' variable at timepoint 1 with the value from timepoint 2?

See Look Ahead and Look Back

Re: Selecting timepoints in longitudinal data

Stanley3 — Thu, 18 Jul 2024 17:00:18 GMT

Brilliant, thank you so much!