question-summary

1.One- and two-sided trend tests comparing strata survival curves in PROC LIFETEST https://support.sas.com/kb/19/854.html

2. nodupkey(by key variables) vs nodup (by all) https://www.listendata.com/2013/10/sas-identifying-and-storing-unique-and_7.html#:~:text=The%20NODUPKEY%20option%20removes%20duplicate%20observations%20where%20value,explained%20in%20detail%20below%20with%20SAS%20codes-%20NODUPKEY