Allowable values for --ENRF are "BEFORE", "DURING", "DURING/AFTER", "AFTER" and "U" (for unknown). If --ENRF is used, then --ENRF = "AFTER" means that the event did not end before or during the Study Reference Period. Although "COINCIDENT" and "ONGOING" are in the STENRF codelist, they describe timing relative to a point in time rather than an interval of time, so are not appropriate for use with --ENRF variables.