My understanding is that there is considerable use of the PREMIS Event 
description.   The semantic unit eventDateTime is defined as "The single 
date and time, or date and time range, at or during which the event 
occurred."  I'm wondering if any of you have felt a need to also have a 
timestamp indicating when the Event description was written.  I can see 
two use cases for this.

The first case is widely applicable. Re-reading TRAC (Trustworthy 
Repositories Audit and Certification), I noticed it gives a lot of 
emphasis to records being contemporaneous.  That would indicate that the 
smaller the time between the event happening and the event record being 
recorded the better.  You could only tell, however, if there was an 
indication of when the event record was written.

The second case may only apply to us, I don't know.  We store multiple 
copies of our AIP, each considered a master, in different storage 
pools.  (We also take back-ups of our masters, but that's irrelevant to 
this.)    Programs continuously check the fixity of each storage pool, 
so we know that every AIP in the pool is fixed.  However, we only record 
a fixity Event for the AIP when another program verifies that all master 
copies of an AIP have been fixity checked successfully.  The date of the 
most recent check will vary from copy to copy, so we record in 
eventDateTime the earliest of the dates, which is the most recent date 
we can be sure all copies were good.  That date can be days or even 
weeks before the event record is written.

Do any of you timestamp the time the event record is written, even 
though there is no PREMIS element for it?

Do any of you think an element for the timestamp of the recording of an 
event would be useful?

p