Indexes & Abstracts: Definitions
- Index-- A tool which provides access to some body of information by a "pointer" derived from the original.
- Examples of pointers: author names, subject terms, chemical formulas, cited references.
- Abstract -- A brief summary of the content of a document.
Considerations in Selecting an Index for Searching
- Chronological coverage
- Access points
- For electronic indexes, Interface features
- What subject areas 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, cover less irrelevant material and/or have specialized indexes useful to your search. Example: Catalysts and Catalysed Reactions
- What kinds of documents are covered?
- Most indexes are aimed primarily at journal articles. Example: Academic Search Complete.
- Others specialize in conference papers, technical reports or patents. Examples: NTRL for technical reports; Conference Papers Index for reports and conference papers; ProQuest Dissertations & Theses for dissertations.
- Some cover multiple document types. Example: Chemical Abstracts/Scifinder, Web of Science.
- How much of the world literature does it attempt to cover? Some are limited geographically.
- Example: Though both cover medical literature worldwide, MEDLINE/PubMed favors US literature; EMBASE favors Europeanmedical literature.
- ProQuest Dissertations & Theses only covers North American and European dissertations.
- Everything or just "the best"?
- Chemical Abstracts/SciFinder attempts to cover all of the chemical literature.
- Science Citation Index/Web of Science goes by the rule "20% of the journals publish 80% of the literature" and only indexes the top journals in each field, as measured primarily by citation count.
- What years does the source cover?
- Few sources do retrospective coverage, i.e. indexing the literature before the index began publication. But some do: Science Citation Index has been extended online back to 1900 (though UCSB only has access back to 1945.) Chemical Abstracts Service has now started retroactively indexing pre-1907 literature in its online databases.
- Many electronic sources didn't originally go back as far as the corresponding printed tools. That, too, has changed in many cases. In addition to the Web of Science version of Science Citation Indexand SciFinder (see above), the Compendex, INSPEC and BIOSIS databases, among others, now extend all the way back to the beginning of the printed indexes.
- Sometimes you only need recent years. For example, in biotechnology or particle physics, information dates quickly. Not so in synthesic chemistry, taxonomy, geology, or mathematics, however.
- How often does the index come out? Online is usually faster than print, which may be faster than CD-ROM. Since almost all indexes are available online these days, using print editions for current material is usually a bad choice.
- How much time lag between publication of the original document and its appearance in the index does the index have?
- Web of Science is very fast...since it doesn't do detailed indexing.
- May vary depending on type of document and source of document. Chemical Abstracts does rapid indexing for a set of key chemistry journals, slower processing for others. Similarly, patents from several key patent issuing authorities get rapid indexing. Technical reports and dissertations are delayed further since CAS uses secondary sources for that information.
- To get an idea of the indexing lag, compare the publication date of the most recently issued publication of the type you are interested in to the date of the index.
- Subject indexing
- Some use keywords from document titles and/or abstracts. Example: Biological Abstracts in print and some older years of Science Citation Index use title keywords only. The Web of Science version of Science Citation Index uses title and abstract keywords. Chemical Abstracts weekly issues in print used text keywords.
- Some use standard subject headings or classification codes, like the Chemical Abstracts volume indexes or Index Medicus. Such indexes may have a thesaurus - an alphabetical listing of headings with cross-references to broader, narrower and related terms.
- Many electronic files use a combination of keyword searching and assigned subject headings or classification codes.
- Keyword indexing responds more quickly to new concepts, may be easier for quick, limited searching.
- For some documents, indexers enhance the author's title and/or abstracts with additional keywords. Used often in patents.
- Subject headings and classification codes bring related concepts together regardless of jargon; are better for browsing and comprehensive searching.
- The combination of the two provides maximum power and flexibility; in electronic forms, it lets you use keyword searching as a first step to discover the assigned headings or codes which apply.
- Author Access
- 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 in its early years), some use full names where available (example: Chemical Abstracts).
- Some try to bring different forms of an author's name together; most don't.
- Some are now allowing searching by unique author identification numbers, such as ORCID or ResearcherID.
- Access points -- Specialized indexing
- Corporate source / Affiliation of authors
- Useful for locating the research of a given company.
- Can be combined with author searching to distinguish authors with similar names.
- Geographic indexing -- common for biological, environmental, geological indexes.
- Genus/species indexing
- Chemical substance indexing
- A specialized form of subject indexing.
- Some index individual compounds; example: Chemical Abstracts
- Some index classes of compounds.
- Some index compounds and component elements.
- Indexing may be by name (sometimes multiple forms), chemical formula or structural feature.
- More sophisticated forms, such as structure, reaction, substructure or similiarity indexing usually are available in electronic tools only.
- Patent indexing
- Indexes by patent country and number, as well as inventor and patent assignee. Subject indexing may take advantage of classification codes in national or international use.
- Concordances relate "families" of patents from different countries.
- Numeric data indexing
- Especially useful for engineering data, some databases allow you to search for numeric data (e.g. length, volume, velocity, electrical power, luminosity), specifying units and numerica values or ranges of values.
- Citation Indexing
- Connects cited papers to citing papers.
- Can be effectively used for subject searching, based on the premise that an author only cites papers which are directly relevant to the current paper.
- Some electronic forms use co-citation techniques (e.g. Related Record searching.)
- Combining access points
- By their nature, print indexes rarely allow combination of different access points, such as author and keyword.
- Electronic indexes can allow combinations of multiple access points (and usually have more access points to begin with...)
For electronic indexes, the same considerations of interface features apply as in online catalogs. (See Lecture 3.):
- Search features -- Basic vs. advanced searching; truncation, Boolean searching, proximity searching, search limits.
- Display features -- Short vs. long record displays; record sorting options; record marking; printing/downloading/e-mailing records; linking between records and/or to full-text sources. Many electronic indexes nowadays have features to analyze and/or refine answer sets.
- Personalization features -- Settable preferences; Stored searches and/or answer sets; Alerting services.
- Help features -- On-screen examples; In-context help; Indexed and/or searchable help screens.
Federated Searching -> Discovery Tools
"Federated searching" is a bit of library jargon that refers to systems that allow you to search multiple databases at the same time. Frequently, you can do this with databases available on the same platform (e.g. any or all EBSCO databases; any or all ProQuest databases; any or all Web of Science databases.) Sometimes a third-party search interface will let you search multiple databases at once - for example, the WorldCat Discovery interface allows you to search multiple article indexes at the same time as you search the Worldcat catalog. Federated searching is now frequently being recast as discovery service. See lecture 3 for more discussion of this concept.
Note, however, that generally any federated search only allows you to use search features that are common to all the databases involved - in other words, a "lowest common denominator" search. As a result, federated searching can save you time, but it may force you to do a less sophisticated search than you might be able to do in any of the individual databases.
© 2022 Charles F. Huber
This work by Charles F. Huber is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
Based on a work at guides.library.ucsb.edu