Evaluating Sources: Choosing the Right Tool

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 factors

• What years does the source cover?
• Many electronic sources don't 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 doesn't 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, singular/plurals
• The combination of the two provides maximum power and flexibility;
• Author Indexing
• Nearly all indexes have an author index but...
• Some don't 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.

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