Controlled vocabularies

I've joined a study group! :) Well, two of us have decided to get together to study once a week so we can tackle this next assignment head on, and to help each other understand the concepts. Should be good. We had a sesh on Wednesday and talked through the answers to some of these questions which was helpful. I wasn't up to this module yet, which made it a little tricky, but we got there, and it made it easy to finish the module when I did get up to it today! :)

5.6 Exercise 2
1. Explain what is meant by specificity in indexing.
How precise the terms are – they need to be specific to that item. Not talking about the genre, but the example of the genre that is being indexed. A book about possums should be indexed under the heading possums rather than marsupials (Hider, p. 135).
2. Explain what is meant by co-extensive entry.
If there is more than one subject in the document, there needs to be headings for all of them, not one heading to summarise. So a book called ‘frogs and toads’ would have both frogs and toads as headings. A book about marsupials and mammals will require terms for both (Hider, p. 135).
3. They do it that way because the system was originally devised for card catalogues and hasn’t been changed. It is not appropriate for an online environment – it is unnecessary, and does not feel natural.
4. Free floating subdivisions – subdivisions that fit under many different headings, e.g. research would fit under library as well as business (and probably many others too). A subdivision is a qualifier under a heading to make it more specific (p. 138).
5. The main differences between thesauri and lists of subject headings:
Thesauri are used in defined subject fields (such as psychology or geology), whereas subject heading lists cover a wide range of subjects. Thesauri use specific terms, whereas subject heading lists usually use more general terms. Subject heading lists can have subdivided headings, unlike thesauri. Thesauri use single terms, so cannot use pre-coordinate searching, unlike subject heading lists. And Thesauri closely define the relationships among terms, whereas the subject heading lists do not always do so. (Hider & Harvey, p. 146.)
6. A scope note (SN) “indicates when to use the descriptor, defines scope” – it gives a definition of the descriptor so it is obvious when it is appropriate.