Teaching Chemical Information:
Tips and Techniques

— August 1998 —

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
• Comprehensiveness
• Chronological coverage
• Access points
• Quality

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).

Grace Baysinger, Head Librarian and Bibliographer
Swain Chemistry and Chemical Engineering Library, Stanford University Libraries
graceb@stanford.edu