Thanks to John Hostage, Deborah Leslie and Gary Strawn for their responses, each of which contributed information new to me. I edited NAR n 83213769 to conform with EDTF 5.3.3 and suggest that 5.1.3, Interval, be merged with 5.2.3 Extended Interval. I retained the month and day as I calculated them. Although LC-PCC does not allow unnecessary addition of subfield d to an authorized access point, it is not prohibited with variant access points and can help users.
Deborah's observation gives a simple and handy means to compute the possible years of birth for use when the month and day are not judged significant. This technique is not self-evident to everyone, however - hence my computations. I have wondered about future use of field 046, as perhaps in its application with linked data, and cannot answer John's question concerning what purpose a precise range of dates will serve. I also wonder whether Gary's authority toolkit will supersede the OCLC macro.
Sincerely - Ian
Cataloging and Metadata Services Librarian
George Mason University Libraries
[log in to unmask]