A recent discussion on the RDA-L list brought to light some
information about FRBR relationships and how RDA creates (or does not
create) identifiers for linking between work, expression,
manifestation, and item. (WEMI)
The key information is in chapter 17, which is only 17 pages long (and
a lot of it is examples). What is significant for this project is that
links between WEMI consist of "preferred access points" that represent
the FRBR entity. For example, there can be an author/title access
point that represents the work ("Schumann, Clara, 1819-1896. Scherzos,
piano, no. 1, op. 10, D minor"). A expression access point represents
the expression of the work ("Blade runner (Motion picture : Final
cut"). Some works and expressions have LC authority records, and the
ID number of the authority record may be considered an identifier for
the FRBR entity.
The chapter also shows examples using what I see as "external"
identifiers for the FRBR Group1 entities (WEMI). These include the
ISBN or music publisher numbers for manifestations, and the
International Standard Text Code for works. These external identifiers
strike me as problematic for a few reasons:
- coverage is uneven: there are many works and manifestations that
don't have such a code
- coverage is uneven: there are no such codes for expressions
- these identifiers come from another information space, and creators
of RDA data cannot create or correct them when needed
The upshot is that identifying and linking FRBR Group1 entities using
these external identifiers is spotty at best, and decidedly not
consistent enough to create reliable FRBR relationships.
Now for the catch:
RDA does not specify "preferred access points" for manifestations or
items. So we have no "identifier" for manifestations. (not having one
for items is a bit less of an issue, for various reasons). So we can
link from:
manifestation (with an expression access point) to an expression (with
a work access point) to a work
But we can't link from an item to a manifestation, nor can we create
relationships between manifestations. Well, not with what we have
today in RDA.
This came up for us in Alistair's analysis of scenario 2, where he
used the ISBN for the manifestation identifier. I objected, but in
fact there is no actual manifestation identifier to use.
I don't really know what to do at this point, but it would be good to
try to make use of RDA access points as WEMI identifiers in one or
more of the scenarios so we can illustrate the issue. I'll see what I
can do, but may need help.
kc
--
-- ---
Karen Coyle / Digital Library Consultant
[log in to unmask] http://www.kcoyle.net
ph.: 510-540-7596 skype: kcoylenet
mo.: 510-435-8234
------------------------------------
|