Stanford University Libraries

What to Teach: Evaluating Sources: Choosing the Right Tool

Students need standards so they can select the appropriate tool for each information need.

Typical questions and tools

  • Introductory or overview information
    books, reviews, treatises and encyclopedic works
  • Individual pieces of data
    handbooks, tables
  • Original research
    journal/patent indexes

Criteria for Selecting a Source

Scope

  • What subjects does the index cover?
  • Broad scope is useful for comprehensive searches, and "interdisciplinary" topics
    Example: Science Citation Index covers the whole of science, engineering and medicine
  • Narrow scope may be quicker and easier to use, and might have specialized indexes useful for your topic
    Example: Analytical Abstracts

Comprehensiveness

  • What kinds of documents are covered?
    • Most indexes cover journal articles
      Examples: Current Contents, Biological Abstracts
    • Others specialize in conference papers, technical reports or patents
      Examples: NTIS for technical reports; Dissertation Abstracts
    • Some cover multiple document types
      Example: Chemical Abstracts
  • How much of the world literature does it attempt to cover?
    Some are limited geographically or by language
    • Dissertation Abstracts only covers North American and European dissertations
    • General Science Abstracts only includes English language articles
  • Everything or just "the best"?
    • Chemical Abstracts attempts to cover all of the chemical literature
    • Science Citation Index only indexes the top journals in each field (measured by citation count)

Chronological coverage

  • What years does the source cover?
    • Many electronic sources do not go back as far as the corresponding printed tools
    • Sometimes you only need recent years. (For example, in biotechnology or particle physics)
  • How often does the index come out?
    Online is usually faster than print, which may be faster than CD-ROM
  • How much time lag between publication of the original document and its appearance in the index?
    • Current Contents is very fast...since it does not do detailed indexing
    • Currency may vary
      Chemical Abstracts does rapid indexing for key chemistry journals. Technical reports and dissertations are delayed (CA uses secondary sources for that information)

Access points

  • Subject Indexing
    • Some use keywords from document titles and/or abstracts
      Example: Current Contents uses keywords only
    • Some use standard subject headings or classification codes
      Example: Chemical Abstracts volume indexes
    • Many electronic files use a combination of keyword searching and assigned subject headings or classification codes
    • Keyword indexing is effective for new concepts
    • Subject headings bring related concepts together regardless of variations such as abbreviations or singular/plurals
    • The combination of the two provides maximum power and flexibility
  • Author Indexing
    • Nearly all indexes have an author index but...
    • Some do not index all authors of a paper
    • Some use initials for first names (example: Science Citation Index), some use full names where available (example: Chemical Abstracts)
  • Access points — Specialized indexing
    • Chemical substance indexing
      • A specialized form of subject indexing
      • Indexing may be by name (sometimes multiple forms), chemical formula or structure
      • Structure, reaction or substructure indexing are usually electronic tools
    • Corporate source
      • Useful for locating the research of a given company
      • Can be combined with author searching to distinguish authors with similar names
    • Patent indexing
      • Indexes by patent country and number, as well as inventor and patent assignee
      • Concordances relate "families" of patents from different countries
  • Combining access points
    • Electronic indexes allow combinations of multiple access points
    • What access points (fields in online jargon) can be searched?
      Example: In INSPEC you can search for theoretical vs experimental articles; in CA you cannot

Modified from a page created by Chuck Huber (huber@library.ucsb.edu).

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