TABLE OF CONTENTS
Leave page for Thema general information:
Thema Subject Codes
Users want to see Thema presented as ONIX, especially to understand What do you do with a translator entry with a second subject or a qualifier? BISAC and Thema are very similar – both are designed to support trade retail sales and do that by naming a single subject as a "Main Subject" to be used by retailers. One way to think of that Main Subject is that it directs the book to the right retail buyer as most buyers work within subject areas. Librarians tend to work in a similar way with an interested professional specializing in areas. A Main Subject is like saying which book professional would care most about this book. There's a second special concern for Thema in that any subject code that applies to a book can be used (for example "slavery" applied to a work of Fiction) and the main subject would define if the book is fiction or nonfiction in such a case.
Otherwise, while the codes are hierarchical (example below), the actual book subjects are not given in a hierarchy. If the subject describes the book – be it a subject code or a qualifier or a regional code – you use it to describe the book. While both systems allow for as many codes as needed, BISAC codes seldom exceed three. As you'll see, Thema's schema is more granular and may require additional codes. In either case, focused and fewest will almost certainly give better retailer adoption than more volume.
In short: you should mean all the codes you use – they should really describe the book's content.
Codes are hierarchical but not one-to-one between systems
Coding from BISAC 2016 and Thema 1.2:
|BISAC Code||Literal||Retailers can associate this with any of these levels|
|FIC022010||FICTION / Mystery & Detective / Hard-Boiled|
- "FIC" is Fiction
- "FIC022000", the "root" is Mystery OR Detective Fiction
- "FIC022010" Mystery OR Detective + Hard-boiled Fiction
|FIC062000||FICTION / Noir|
- "FIC" is Fiction
- "FIC062000" is Noir Fiction
But this isn't one-to-one, as both of these BISAC codes are mapped to a single Thema code:
|Thema Code||Literal||Retailers can associate this with any of these levels|
|FFL||Crime & Mystery: Hard-boiled Crime, Noir Fiction|
- "F" is Fiction
- "FF" is Crime & Mystery Fiction
- "FFL" is Crime & Mystery: Hard-boiled Crime, Noir Fiction
The US market (BISAC) determined that there was enough noir fiction being sold that wasn't associated with hard-boiled detective fiction to warrant its own code. Thema (international) may come to the same decision at a later date but as of writing has not. You should expect differences between the coding systems. (Note that these examples are based on older versions of BISAC and Thema and should be only used as example. The actual coding and their meaning may have changed).
Here is another example:
- Thema uses the general term Crime to cover "detective" but provides for "mysteries" in a variety of contexts, while BISAC has a specific heading for FICTION / Crime, but combines Mystery and Detective.
- Thema places True Crime as a minor heading under a hierarchy of Literature / Biography & non-fiction prose, while BISAC provides True Crime as a major heading with subdivisions for Espionage and so on.
- Therefore, to reproduce a code to replace a subdivision of BISAC's True Crime, Thema codes may require use of a secondary subject code (like the non-fiction code for "Espionage & Secret Services") to add that meaning to its True Crime subject.
Another difference can be found in their respective "trees" which are represented in the CODES for Thema and in the LITERAL for BISAC. If that sounds confusing think of it as: You put the Thema code list in order by sorting on it's codes but you sort BISAC on its literal (aka description). In either system retailers can take the information provided and move up to a higher level.
BISAC by design is a less granular system than Thema (and that's one of its advantages). Thema offers more opportunities to use secondary subject to paint a picture about the book (and that's one of its advantages). The takeaway is each may offer opportunities to describe your specific book that the translator misses. The translator can get you close but for a specific book one system may support options better suited to the specific title than the options in the other.
A book's overall subject coding is NOT hierarchical
BISAC coding often includes information that, when translated, has to use combined codes values in Thema, and it is hard to understand Thema until you see this. Here's an example:
Imagine you're coding a cookbook of recipes compiled by the chefs in the city of Dijon, France and you've assigned the BISAC Main Subject code:
CKB034000 COOKING / Regional & Ethnic / French
The Thema Main Subject Code would be:
WBN National & Regional Cuisine
A book can only have a single Thema Subject Category code as a Main Subject and in this case Thema would seem to be providing a really poor Main Subject in comparison to BISAC. But this is the code for National & Regional Cuisine and the code list specifies that its entries should be supported by a Thema List 1 Geographical Qualifier Code. So the Thema Main subject is understood fully by using a second regular (a.k.a. additional) code. And in this case you would include the code:
This is a Geographical Qualifier with a national extension that takes it right down to the city within France. Now the BISAC code seems comparatively less rich, as it only allows you to identify French cooking. In Thema the cookbook can be placed geographically by a retailer in Europe (1D), Western Europe (1DD), France (1DDF), and by national extensions (-FR-) provided by French publishers to allow the city of Dijon to be identified as within the regions of Borugogne (-FR-E) and Côte-d’Or 21 (-FR-EA), respectively.
Wait!!! What if my cookbook isn't actually confined to a region within France but it's about French cooking anywhere... What now? Let's not overthink this, the Geographical Qualifier would be:
This is because you're associating the book with the national cuisine of France – the book's main subject is National & Regional Cuisine and implicit in that "National" is the understanding that the geographical marker can identify something broader than just location. And to return to the example: recipes from the region are still implicitly associated with France and therefore within the broader subject of French Cooking. Retailers can still focus on 1DDF and ignore -FR-EAA.
Your BISAC Main Subjects should be as specific as possible – the best possible fit for the book. It's exactly the same for Thema, but some Thema Main Subjects will require the support of a qualifier as part of the regular subjects in order to be complete. Thema's coding can be more verbose with more parts than BISAC, but that just allows more flexibility in an international system. If qualifier support is necessary in Thema it will be clear from the Main Subject Code and you can rely on retailers to understand that. The Thema rule for one Main Subject Code is for simplicity; retailers need consistency in the data. One Main Subject from the subject code list is a lot easier to program for than trying to build a picture from multiple codes. For one thing, how would you decide which are more important? The answer is: none would, or could, be — and that takes us back to the fact that a book's overall subject coding is NOT hierarchical.
A book is either about something or it's not. If someone is looking for information about a particular topic and finds your book by that subject, then the book should be of interest. A book can also be about or set in a place, which is when you would use a BISAC Regional Theme or Thema Geographical Qualifier, but the place is never a Main Subject. (It can involve a subject like geography and be about a specific place but a set of coordinates is not a subject let alone a Main Subject.)
Main Subject exists as a convenience for retailers. Otherwise, all the subject codes apply because they all describe the book's content. In the above example, the BISAC code provides a place-like association within the code but that's a luxury you can support in a single market like the US where consumers buy books on French Cooking. Thema supports the same need in a similar but more flexible way that allows any country to have a national cuisine. Thema Qualifiers are simply a way to add information about the book's content.
An argument can be made that subjects could be ranked, in that one subject may have more content devoted to it than another – a way to say "it's more about this than that." If it's a concern, try to ensure that your subject coding follows that ranked order in the ONIX file and retailers will likely preserve it. ONIX doesn't support ranking for subjects as a formal option because trade retail subject coding should be focused enough to make it unnecessary.
I'm selling cookbooks and I've decided that my market is travellers who may be interested in a particular region. While the (main) focus is on recipes, my books include extensive language instruction (not to mention nutritional charts) about the dishes, methods, and ingredients of that area. They sell like crêpes chaud. What's more, I've discovered that many children buy these books for their moms because the books are beautiful and remind their moms of home, and that parents buy them for their kids who are about to go travelling. Both Mother's Day and graduation season experience sales spikes.
So with that improbable scenario (and note that even in this illustration I've grounded my subject choices to show the information I'm providing is genuinely useful, however idealized, to retailers), my ONIX might look like this. See if you can figure out what the book is about and note how Thema provides more precision than BISAC does. The difference between ONIX 2.1 and 3.0 are minor so I've provided only the 3.0 version as it's simpler and cleaner to present.