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Module 5: Providing subject access to resources

Posted by arlekeno on August 17, 2012

Just so you know Essay was done with several hours to spare.

Very relieved to have it done considering how many hours i put into it,

and I just hope that the marker is a starwars fans since I catalogued Princess Leia’s Message to General Obi wan.

Anyway, ETL505 Next module.


Starting off interesting, About half of the Searches are for a SUBJECT area. good to know.  (os the most common need, so providing good subject access is important)

Explanation of derived v Assigned Indexing. Points on teh search spectrum I guess.

As well as the spectrum idea, another useful way of thinking about how we provide subject access to information resources is by considering where the words or text we search on come from. Derived indexing takes words (derives them) from the document. Assigned indexing takes words from somewhere else (for example, from a list of subject headings or a thesaurus) and assigns them to the document.

I really need to know the difference between .scisshl and .SCot ( as well as provenence)

Time to read Chapter 6: Subject access concepts pg99

This has traditionally involved deciding what the information resource is about, translating that into terms (words and phrases) or symbols which represent the subject, and providing access to these terms and symbols through the library information retrieval system.
pg 100: Subject area crossroads, three paths diverge:

  1. Controlled Vocabulary: the traditional way, using subject headings, Thesauri, Bib Classification schemes.
  2. Derived indexing: Taking words directly from the text. Natural language.
  3. The Middle way: A mix of controlled vocab and natural language aided by Metadata (e.g. publisher,

Terms to know when creating subject access

  • Exhaustivity:  how many subjects do we assign? How exhaustive is the detail?
  • Literary warrant: Only accommodate subjects which already have works produced about them.
  • pre-coordination: Indexing stage (are we joining concepts together e.g. Sharp programmable calculator)
  • post coordination:search stage (joined after the the creation of entry, in boolean search)

All judged by Relevance, Recall and precision.


Subject access  Literary warrant
Indexing language Pre-coordination
Controlled vocabulary  Post-coordination
Derived indexing Natural language
Assigned indexing Free indexing language
Exhaustivity Classification scheme

A couple of the terms that may cause problems are pre-coordination and post-coordination. Harvey and Hider’s distinction is that single-concept terms can either be combined (coordinated) at the indexing stage (pre-coordination) or at the search stage (post-coordination). Bear in mind that the indexing in many computer systems allows users to search certain fields for keywords and phrases, as well as providing displays of precoordinated strings for browsing.

Ok, 1, I think I answered above, as with 2. And 3 is on page 103 of the text. Exercise 1 – Review questions

1. Explain the difference between derived indexing and assigned indexing.
2. Explain the concept of exhaustivity.

3. Outline the main weaknesses associated with the use of a controlled vocabulary.

Answers are at the end of this module


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