The genre and medium variables are used inconsistently across styles and CSL clients, and this leads to some difficulty in programming style that yield consistent and expected behavior.
tl;dr
I think that genre should be explicitly described and understood as referring to item subtypes and never as referring to subject matter or topical genre. medium should be used to describe item format or medium. Topical genre/subject matter should be mapped to a new CSL variable or not at all.
Longer discussion
Back in 2007, Bruce D’Arcus commented that “genre” should probably have been called “type” or something similar. That seems to be how it is (at least nearly) universally used in CSL styles. Zotero, Papers, and most (all?) other client programs map “type”-like fields to genre for many item types (e.g., report, thesis, manuscript, post, post-weblog, webpage). However, genre is used as a description of subject matter for motion_picture (Zotero). Zotero also uses genre for Programming Language for Computer Program; that would probably be better labeled more broadly as “Program type”. Mendeley provides genre for all item types and labels it as “Genre”, so it is unclear what the intended use is. However, given its label, I imagine that at least a fair number of users store things like topical book genres in the field on Book, Book Section, Motion Picture, and similar items. The CSL specification also provides subject matter for books and films as an example use of genre.
medium is used by Chicago, MLA, APA, and other styles to describe the medium or format of items (e.g., CD) or as a general descriptor of unusual features of the items. Mendeley doesn’t map anything to medium. Zotero uses medium to describe the artistic medium and/or physical/recording format for graphic, song, broadcast, and
interview. Zotero also maps Computer Program “System” (Operating System?) to medium. I’m not sure that that necessarily needs to be mapped to a CSL variable at all (is it ever necessary to cite the operating system of a program? in the few edge cases where that might matter, wouldn’t it generally just be discussed in the text?). If it does get mapped, medium is probably the closest match, but that would probably yield inaccurate references for most styles using medium (e.g., it might yield “[Computer Software, Windows]” in APA).
I don’t know that CSL needs to provide a variable for the subject matter of an item, if it does, it should be a new variable (e.g., maybe category or subject-matter), rather than continuing to use genre for a mix of “subtype” and “subject matter”. Either way, I think that CSL should explicitly advise style developers and clients that genre should not be used for “Genre” in the subject matter sense and instead should only be used for “type”-like variables. “Genre” as a user-facing label for this field seems too ambiguous to promote expected user behavior.
A recommended mapping/user-facing label set might be:
-
genre– “Type” -
medium– “Medium” or “Format” - none – “Genre” or “Category” or “Subject” or “Topic”
I posted some thoughts on the old mailing list that don’t seem to have made the migration to Discourse:
http://xbiblio-devel.2463403.n2.nabble.com/APA-6th-using-OWL-rather-than-APA-td7579413.html#a7579525My
I copied the text from there below, but my thinking is a bit evolved since then.
In that post, I suggested that medium might have in retrospect been a better choice for all format and subtype information (i.e., for both the format of book being read and things like type of thesis, report, forum post, etc.), rather than using genre for such information for some item types (report, post, thesis, etc.) and medium for others (graphic, song, etc.), while also using genre to provide information about item topic (topical genre for book, song, motion_picture, etc., but also potentially things like purpose of computer program [reference management, statistical analysis, etc.] or purpose of interview or letter).
It might be possible to switch to using medium for “type”-like uses of genre. I’m not sure whether that’s feasible given the ubiquity of genre for this purpose in styles (though given the dearth of using medium, switching genre to medium could happen mostly programmatically), web translators (same as above), and client programs (obviously the most challenging). Probably a bigger question is whether “type” and “format” are always interchangeable in their meaning and citation rules. APA, for example, has rules ithat seem to suggest that a report might have both a “type” (e.g., “NIH Publication”, as in “NIH Publication No. 123”) and a format (e.g., “Brochure”) and that both should be included when applicable. However, all of their examples give either one or the other, so this rule could instead by handled using some simple conditional formatting. I’m not sure whether “type” and “medium” have different requirements in other styles.
Given the potential for different needs for type/format and the embeddedness of genre for type, I think the best way forward would be to keep “type” and “format” as separate CSL concepts and to add (or ignore) “subject matter/topical genre” as a separate concept/variable. Following this idea, genre should be exclusively used for “type”, medium for “medium/format”, and a new variable (or none at all) for “subject matter/topic”. Adjusting styles as necessary and getting clients on board seems fairly feasible for this change (e.g., it requires only to change the “Genre” label to “Type” in Mendeley).