Is there any plan to define a subfield in 5xx fields in authority records to indicate the time period when the relationship was valid?
I have this situation (which I often encounter in my work), where multiple fields of the same relationship appear in one record:
510 2 ǂi Hierarchical superior: ǂa National Science Foundation (U.S.) ǂw r
[true from January 28, 1985 to July 22, 2010]
510 2 ǂi Hierarchical superior: ǂa National Science and Technology Council (U.S.) ǂw r
[true since July 22, 2010]
I wish it were possible to use "ǂs 1985 ǂt 2010" (but, of course, ǂs and ǂt already represent other data elements). I wish inputting exact dates were possible, as I think I have seen agencies change organization twice in a year, and definitely I have seen year-to-year changes.
If these fields display (especially to the public), it would be very desirable to indicate which body was superior at which time. As it is now without qualification, it looks confusing to me or looks like the record creator got two similar names mixed up (non-technical service staff do not see 670 fields).
It is possible that multiple hierarchical superior bodies are concurrent or overlap partially in time, so without being able to qualify by dates the situation as presented now looks ambiguous. And it would be helpful to qualify by date for all other types of 5XX relationships.