When EPOCH is included in the Adverse Event domain, it should be the epoch of the start of the adverse event.
In other words, it should be based on AESTDTC, rather than AEENDTC.
The computational method for EPOCH in the define.xml should describe any assumptions made to handle cases where an adverse event starts on the same day that a subject starts an epoch, if AESTDTC and SESTDTC are not captured with enough precision to determine the epoch of the onset of the adverse event unambiguously.