Q35: Can topical headings (tag 150) be used as genre/form terms in bibliographic records (tag 655) if there is not a corresponding genre/form authority record (tag 155)?
A: The Policy and Standards Division realizes that some libraries would like to use genre/form terms for disciplines in which LCGFT authority records have not yet been made (e.g., literature). The use of topical LCSH headings as genre/form terms is allowed for those disciplines, depending on the meaning of the topical heading.
LCSH headings (tag 150) assigned to a 655 field in lieu of an authorized LCGFT term should to be coded with second indicator 0 (zero), indicating that they are authorized by LCSH.
By this guideline, if there is an authority record for the LCSH string, and it indicates it can be used for works _of_ a given type, or the cataloger concludes that it can be, then I think it can be used in a 655. But if it is a constructed string, I would be dubious. Constructed strings are not generally used for works _of_ a given type unless it has a $x subfield. If it has a $x subfield, then I think the 655 should be based on the $x subfield, not the entire string.
I doubt that there are very many LCSH strings that would be appropriate as a genre term. Do you have some examples?
I know that LCGFT headings may not be subdivided—“neither topically, geographically, chronologically, or by form,” as says the Genre/Form Terms Manual.
But if an LCSH heading is used in a 655—with second indicator 0, of course—is it legal to subdivide it? I’m thinking not but wanted to ask.