Re: Discussion of id.loc.gov

OK, I did a blog post at:
http://kcoyle.blogspot.com/2009/05/lcsh-as-linked-data-beyond-dash-dash.html

Here's a cut and paste:

The SKOS version of LCSH <http://id.loc.gov/authorities/> developed by 
LC has made some choices in how LCSH would be presented in a linked-data 
format. One of these choices is that the complex headings (which is the 
vast majority of them) are treated as a single string:

    Italy--History--1492-1559--Fiction


While this might fit appropriately as a SKOS vocabulary, in my opinion 
it does not work as linked data. I'm going to try to explain why, 
although it's quite complex. Part of that complexity is that LCSH is 
itself complex, primarly because there are many exceptions to any 
pattern that you might care to describe. (For more on this, I suggest 
Lois Mai Chan's Library of Congress Subject Headings, 4th edition, the 
chapter on geographic subject headings, pp. 67-89)

Taking the heading above, as I mentioned in my previous post, the 
geographic term Italy is not in LCSH even though it can indeed be used 
as a subject heading. Instead, Italy is defined as a name heading in the 
LC name authorities file. In that file, and only in the name file, 
alternate forms of the name are included (altLabels, in SKOS terminology):

    451 __ |a Repubblica italiana (1946- )
    451 __ |a Italian Republic (1946- )
    451 __ |a Wlochy
    451 __ |a Regno d’Italia (1861-1946)
    451 __ |a It?alyah
    451 __ |a Italia
    451 __ |a Italie
    451 __ |a Italien
    451 __ |a Italii?a?
    451 __ |a Kgl. Italienische Regierung
    451 __ |a Ko¨nigliche Italienische Regierung


There are no altLabels in the LCSH entry for Italy--etc. And because the 
term Italy is buried in an undifferentiated string, there is no linked 
data way to say that the Italy in Italy--History--1492-1559--Fiction is 
the same as http://id.loc.gov/authorities/n79021783, which will 
presumably be the URI for the name.

It is assumed in LC authorities that the altLabels for a name term that 
appears in a subject heading apply to both the name used as a name and 
the name used as a subject heading. In the card catalog, where the name 
alone would appear first in the alphabetical browse of the cards, it was 
only necessary to make references to that "head" of the list, which 
would, in our case, be Italy alone. This has caused great problems in 
online catalogs where searching is by keyword, not a linear alphabetical 
search. Some systems manage to get around this by doing a string compare 
to the same subfields in name headings and subject headings, and then 
transferring the altLabel forms to the related subject headings.

    $a Shakespeare, William, $d 1564-1616
    $a Shakespeare, William, $d 1564-1616 $v Adaptations $v Periodicals

In this case, the $a and $d subfields represent the same authoritative 
entity. The rules say that they are, and must be, the same authoritative 
entity. If they don't match exactly then someone has done something 
wrong. They are both instances of a name identified as "n 78095332", and 
which will presumably be given the URI 
http://id.loc.gov/authorities/n78095332. There is no question about that.

There is also no question that when the name is used in a subject 
heading it has the full meaning that it is given in the name heading 
record, including alternate forms of the name and the many notes fields 
provided by the catalogers that created the authority record. That this 
don't appear in the LCSH file does not mean that it is not the case: it 
means only that the LCSH record assumes that the name record exists and 
provides that information, and that the information is applied to the 
name in the subject entry through the linear nature of the dictionary 
catalog.

We musn't confuse the form with the meaning. That LCSH has a rather 
arrested form is unfortunate, but it was never intended to be used 
outside of the context of the full set of authorities that gives full 
treatment to those things that have "proper names." (c.f. Chan, chapter 4)

If we wish for the LC authorities to be used in a linked data 
environment, then we have to make sure that the linking capabilities are 
there. Although I agree that each LCSH record has an identifier, and 
that identifier should be used, I don't agree that what is expressed in 
the LCSH record is a dumb, undifferentiated string. In this post I have 
addressed the relation to name headings, but there are other uses of 
controlled vocabularies within the subject headings that I haven't fully 
investigated yet.


-- 
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Karen Coyle / Digital Library Consultant
kcoyle@kcoyle.net http://www.kcoyle.net
ph.: 510-540-7596   skype: kcoylenet
fx.: 510-848-3913
mo.: 510-435-8234
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