@ballardw already provided a working solution "long ago". What prevents you from using it? proc format; picture mydatetime_dow low-high ='%0m/%0d/%Y %3a' (datatype=datetime) ; run; data example; specimen_recv_time=datetime(); specimen_recv_time_2=datetime(); format specimen_recv_time_2 mydatetime_dow.; run; proc print data=example; format specimen_recv_time mydatetime_dow.; run; proc contents data=example; run;   ... View more

A data step solution would look like:   data have; input ID GROUP $ DATE :mmddyy10.; format date mmddyy10.; datalines; 1 AAA 1/1/23 2 AAA 1/1/23 3 AAA 1/10/23 4 BBB 1/1/23 5 BBB 1/2/23 5 BBB 1/3/23 ; data want (keep=id average); set have ; by group; date_range+dif(date); if first.group then call missing(date_range,n_ids); n_ids+1; if last.group; average=n_ids/(date_range+1); run;   ... View more