Hi all, I had this situation where I choose the onset date ranging from 01/01/2011 to 12/31/2011 and follow up until 12/31/2013. Therefore I need to exclude all the ID's with onset after 12/31/2011 on the first observation. For example, in the below scenario there are multiple observations for each ID.  I want to delete all those ID's which had first onset occur after 12/31/2011.  Data I have ID Order of admission Onset 1 1 02/09/2011 1 2 04/30/2012 1 3 08/12/2013 2 1 07/27/2011 3 1 05/11/2012 3 2 12/25/2012 4 1 11/09/2013 5 1 05/15/2011 5 2 08/22/2011 Data i want to keep ID Order of occurrence Onset 1 1 02/09/2011 1 2 04/30/2012 1 3 08/12/2013 2 1 07/27/2011 5 1 05/15/2011 5 2 08/22/2011  I am a beginner of SAS and use SAS 9.4. Please help me. Thanks in advance for the support.  ... View more

Hi all, I had this situation where I need to exclude all the ID's with history is 1 on the first observation. For example, in the below scenario there are multiple observations for each ID.  I want to delete all those ID's which had history of disease (=1) on the first observation.  Data I have ID Order of occurrence History 1 1 1 1 2 1 1 3 1 2 1 1 3 1 0 3 2 1 4 1 0 5 1 0 5 2 1 Data i want to keep ID Order of occurrence History 3 1 0 3 2 1 4 1 0 5 1 0 5 2 1  I tried so many time but i can't get the result I want. Please help me. Thanks in advance for the support.  ... View more