Defining Entities
for Description
The Bibliographic Universe
Why bother?
Why define a set of objects to describe?
Can’t we just let everyone tag everything, no
matter what it might be?
Slide 2
The utility of limits
Free tags don’t specify a descriptor’s context (does
the descriptor indicate the resource’s subject? the
date of creation? the date of revision? the author? a
comment?).
By restricting the scope of description through
specifying a more specific set of objects, we enable
the definition of more specific attributes and more
precise description...and thus more relevant results.
Slide 3
Relevance
Relevance: a key concept in determining retrieval effectiveness. Are results
relevant to a searcher’s need?
The basic retrieval measures are precision and recall.
• Precision: Of the results retrieved, how many are relevant?
• Recall: Of the relevant results in a collection, how many are in the results
set?
A search with perfect precision and recall means that all the results are
relevant, and no relevant resources were not retrieved in the search. In
practice, there tends to be a point at which an inverse relationship between
precision and recall obtains: a system that delivers more precise results
tends to inhibit recall, and so on.
Slide 4
The bibliographic universe
The set of resources that we most commonly
store, describe, and make accessible in libraries
(and other information systems).
We might say that a straightforward entity in the
bibliographic universe is the book. But when we
say book, what exactly do we mean?
Slide 5
Wilson’s bibliographic universe
Wilson’s idea of the bibliographic universe involves the
following types of related entities:
• Works.
• Texts.
• Exemplars.
Bibliographic control involves our ability to manipulate
this universe to find the best material for our needs.
Slide 6
Exemplars
According to Wilson, an exemplar is a particular
“copy” or “performance” in which a specific
“sequence of words and auxiliary symbols” is
expressed. Exemplars might be:
• A particular physical copy of a book.
• A recitation of a poem.
• The filmed performance of a play.
Slide 7
Texts
According to Wilson, a text is the “sequence of words
and arbitrary symbols” that an exemplar puts into
physical form. While a single text can be expressed in a
variety of forms, the text itself is an “abstract entity”
without physicality. Examples of texts include:
• The sequence of words and symbols that makes up
Wilson’s chapter “The Bibliographic Universe.”
• The sequence of words and symbols that constitutes
the folio version of Macbeth.
Slide 8
Works
According to Wilson, the work is a “group or family of
texts.” However, the extent of this family is not easy to
determine. Examples of works:
• “The Bibliographic Universe” and its translation into
French (er, if it is a strict translation).
• The combined set of editions of the Chicago Manual
of Style.
Slide 9
One work or multiple works?
• Marianne Moore’s poem “Poetry” (beginning
“I, too, dislike it”) was revised multiple times
by the author over 40 years, in varying lengths
of 30, 29, 13, and 3 lines.
• According to my friend Trent, Hans Gabler’s
1984 edition of Ulysses is an “abomination”
and not to be dignified as part of the same
work.
Slide 10
Why care about works?
In some sense the work is the “basic level” of a
document, the one that comes most readily to mind.
When looking for a document, we may not even know
that multiple texts (or versions) exist, but we know that
we want Hamlet.
If the catalog shows us all the texts and exemplars that
make up the work, we can decide which we want. Or we
can just pick any exemplar if the distinctions don’t
matter.
Slide 11
Non-textual materials in
Wilson’s bibliographic universe
For Wilson, images and music are not part of the
bibliographic universe, although there “is no sharp
boundary” between the pictorial and musical universes
and the bibliographic one.
Wilson makes this distinction on a pragmatic basis,
because images and music seem to require different
types of attributes than writings. What does it mean for
a picture or musical work to have a subject, for
example?
Slide 12
What is the work?
• Musical performance (or any performance).
• Documentary film footage.
• Multiple player online games (Megan Winget’s
project to archive and preserve such games).
Slide 13
Documents or information?
Is the idea of a bibliographic universe
outmoded? Should we instead be thinking about
the information universe?
Wilson says that documents are often useful or
interesting in ways that transcend the
information they contain.
Slide 14
Functional Requirements for
Bibliographic Records (FRBR)
FRBR is an entity-relationship model to describe
the bibliographic universe, developed by the
International Federation of Library Associations
(IFLA).
FRBR is meant to model a user view of
bibliographic entities and be independent of any
particular metadata implementation.
Slide 15
FRBR entity-relationship model
FRBR entities
include works,
expressions,
manifestations,
and items.
Chart from Tillet, 2004
Slide 16
FRBR works
A work in the FRBR model is similar to the work
described by Wilson: “a distinct intellectual or
artistic creation.” FRBR examples of works:
• All editions of an anatomy textbook.
• A Bach organ fugue and an arrangement for
chamber orchestra.
• A French movie with English subtitles.
Slide 17
FRBR expressions
An expression in FRBR is similar to Wilson’s text: “the
intellectual or artistic realization of a work” in a form,
be it textual, sound, image, musical notation, whatever.
The expression encompasses the intellectual but not the
physical form (e.g., typeface and layout are not part of
the expression). Examples of expressions:
• The score and performances of a quintet.
• A German text and its English translation.
Slide 18
FRBR manifestations
A manifestation in FRBR is the realization of an
expression in a physical medium. The same expression
can be embodied in different manifestations. All copies
that are produced as part of the same set are the same
manifestation. Examples of manifestations:
• The same performance of a musical work on CD and
on LP (two manifestations, one expression).
• The same edition of a newspaper in print and in
microform (two manifestations, one expression).
Slide 19
FRBR items
An item in FRBR refers to the actual physical
copy of a manifestation. Examples of items:
• A particular autographed copy of a book.
• A particular copy of a musical score in which
one page is missing.
Slide 20
User tasks for FRBR entities
The FRBR report identifies four tasks that users
should be able to accomplish with all the entities:
• Find.
• Identify.
• Select.
• Obtain.
Slide 21
Attributes and entities in FRBR
Each entity has a different set of attributes.
Some attributes are similar: works and expressions both
have titles. (The title of a work, under which
expressions are grouped, might be Hamlet, but the title
of a particular expression might be William
Shakespeare’s Hamlet.)
Some attributes are completely different. Manifestations
have publishers. Works don’t.
Slide 22
Summary
• Defining entities enables more specific description of
objects and more focused searching and browsing.
• The bibliographic universe includes an unclear and
contested number of related entities (works, texts,
etc.) that can be difficult to concretely define but are
still somehow useful.
• Especially for non-textual or new media materials, it
may be necessary to put significant thought into what
constitutes a work.
Slide 23