No subject

properly called SUBJECT SUBDIVISIONS.

If one looks at the Library of Congress Subject Headings (LCSH) volumes and
many, many other thesauri, one sees major topical headings (subject
headings, hereafter, SH) under which various authorised subdivisions
(subd's) are listed, often in a format similar to this (at least in print).
         Ex.  SH  Physics
                       -- History   (an authorised subd)
Electronically one would usually find something like this:
       Ex.       Physics
                   Physics--History

RELATED could give us See Also (SA) or Related Terms (RTs) so that a patron
would be able to examine other areas related to a subject search (or at
least have some related areas identified as existing).

I don't know what happened to Broader Topic/Term (BT) or Narrower Topic/Term
(NT), which should be kept distinct in proper authority control. There
should also be markers for USE  and UF (Use For), which help identify what
form a patron should use.

FREE FORM: I am worried about this usage. In using LCSH etc., there are
free-floating subd's, ones that can go with (almost) any heading. There are
also Pattern Headings (e.g. Fishes in LCSH tells us what subd's are
authorised for ALL Animals) and Form Subdivisions (which identify specific
types of textual materials). Finally, there is the general authority to
create specific personal, geographic and topical SH as needed. Since FREE
FORM might refer to any of these, we definitely need more clarity here.

I thought perhaps AUTHORITY is meant to identify which system (LCSH, Sears,
etc.) but I couldn't guess about LIB or OTHER LIB.

> ... Obviously a pointer to a web resource on these would
> be wonderful, but I am thinking specifically in terms of what
> they refer to in Koha.

We'll have to wait on more knowledgeable cataloguers or Koha
developpers/users to do that and to clarify what is going on with the Koha
authority/thesaurus terms.

> 2 : Also: I assume the thesaurus values have an effect on the
> SUBJECT field: but what exactly?

The thesaurus tells us what terms we can use in a subject field. With some
systems, you can only enter terms that are fixed in the thesaurus
(authorities) in SH fields, so if you have to add something new,  you have
to add it to subjects first. Other more complex systems allow you to enter
terms in the subject field tag/s and have them appear simultaneously (or at
re-indexing anyway) in the thesaurus.

Even more complex systems will try to stop you if they detect a form that is
similar to what you are trying to enter as a new heading to ensure that you
are not making incorrect entries that split the authorities (e.g. creating
two different forms of the name for the same person, or accidentally
misspelling a word -- both common problems). Authorities/thesauri need
maintenance to ensure that the SHs are correct and vice versa because
CONSISTENCY is CRITICAL to making sure both staff and patrons can rely on
the catalogue.

In terms of values, theoretically (although I've yet to find a system that
actually does this), the SH tags in MARC allow one to code for which system
one is using (second indicator), so one could -- again in theory and
apparently not in practice -- use more than one system in parallel at the
same time. Since most systems' authorities aren't that well-maintained,  it
is more pragmatic to make sure whatever SH system you are using is used
properly and CONSISTENTLY.

I hope some of this helps in the meantime, Matthew. Welcome to the wonderful
world of Koha!

Looking forward to hearing more from other Koha users and the developpers on
this interesting question Matthew has raised.

Cheers,
Steven F. Baljkas
library tech at large
Koha neophyte
Winnipeg, Manitoba, Canada


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