Contacting people for authority control
This page contains some boilerplate text for contacting individuals in the course of authority work. Personal communication is a valid source of information for authority records, and is cited in a 670 field.
While authors, actors, and other people you may contact for authority work will likely appreciate attempts to credit their work, they may also be wary of divulging personal information. By briefly explaining the importance of authority control, without the use of library jargon, these fears may be allayed. Contacting an individual is a good way to break conflicts with similar names after referring to other sources, to settle conflicting information, to prevent future conflicts, or to avoid creating an unqualified personal name.
I am a cataloger at the Folger Shakespeare Library [if cataloging a specific work, perhaps refer to it here]. Part of our work involves making sure our catalog can distinguish between different authors with similar or identical names; our library does this in cooperation with the Library of Congress and other libraries around the world. In order to distinguish your name, would you be willing to share your year of birth, your middle name [or any other information needed]? (Adding a birth date is the preferred way of distinguishing names.)
Thank you for your time, and please let me know if you have any concerns.
As necessary, modify the above text to suit your needs.
Prefer emailing from your Folger address over calling the person.
When you must disambiguate
In those rare cases where you have multiple people with the same name and birth year, or a person doesn't wish to give a birth year, mention it. ("Actually, the database already contains a record for someone else named Jane Johnson born in 1962, so we need another way to distinguish you"). Ask for birth month and day or a fuller form of name--an either/or approach is recommended. Otherwise, asking for a full birth date is probably not necessary and may make the person wary.
You may also be trying to identify the person with an existing authority record, in which case you can ask a question like, "Are you the John Smith who wrote Book Title?" Do this if in doubt, as this will prevent duplication in the authority file.
If the person doesn't respond or doesn't wish to divulge birth year or other information, you will need to resort to other forms of qualification as described in MARC 100 in the authority format
When disambiguation is not technically necessary
If the person has an unusual name--and doesn't respond or doesn't wish to divulge birth year--establish the authorized access point as an unqualified personal name.
Finally, there's all sorts of information a person could give you about themselves that would enrich an RDA authority record, such as associated places. Avoid asking for more information than you need to break a conflict, however. Authority control is important, but there's no need to take more of the person's time than is necessary, nor to make publicly available more information than they're comfortable divulging.