Issues in Science and Technology Librarianship
Reference Librarian and Bibliographer for Chemistry, Chemical Engineering, Mechanical Engineering & Materials Science
Stevenson Science & Engineering Library
According to the Engineering Village 2 (EiV2) web site description, Compendex contains over eight million references from 5,000+ engineering journals, conferences and technical reports. EI's sources cover 175 different major engineering fields and related areas of specialization including aerospace, agricultural, chemical, civil, electrical, and mechanical engineering. Online coverage is from 1969 to the present with weekly updates. With the Engineering Index Backfile, available separately, Compendex goes back to 1884 and contains nearly 10 million records. EiV2 also serves as an interface for other engineering-related content such as INSPEC and its archive.
Easy Search is a Google-style interface with a single box for keyword terms. It searches all the databases available through EiV2 at the searcher's institution with no limits applied and with autostemming on. It would be a suitable default for a primarily undergraduate population.
Quick Search (Figure 1) allows users to combine up to three terms with Boolean operators and limit terms by field. Searches can be limited by document type, language, treatment type, year and most recent database updates. Five browsing indexes allow searching with controlled vocabulary. Since author names are entered as they appear on the papers rather than in standardized form, it is recommended that searchers use this index to find all forms of a name. This is a recommendation that should be heeded. Search tips are conveniently included at the bottom of the page. Quick Search is the default at both our institutions because it allows users to limit their searches initially and choose which database(s) to search.
Expert Search (Figure 2) is not for the casual Compendex user and requires comfort with creating search strings using field codes, included at the bottom of the page. Three additional browsing indexes not found in Quick Search correspond to options for limits in Quick Search.
EiV2 calls Thesaurus (Figure 3) a fourth search option, a fact that may not be obvious to non-librarian users. Essentially, it is a short-cut way to do Controlled Vocabulary searching. Selected terms appear in the search box below the list of terms when checked, and search terms are automatically combined with OR. The default date range is all years to which your institution has access.
The third option for refining results, somewhat unique to EiV2 and introduced in the spring of 2005, is "faceted searching." A Refine Results box to the right of the results list has clusters of ten terms for seven fields (author, controlled terms, classification code, language, document type, year, even publisher) ranked in descending order by number of hits. For more than ten terms, just click more. In Easy Search a user clicks on individual terms which are then AND-d to the rest of the terms in the search statement at the top of the results list preceded by a red X. They call these terms "breadcrumbs" In Quick and Expert Search, users can check the appropriate box or type in a new term and click either include or exclude to add or subtract terms from a search. Each added term has the red X beside it. Clicking on the X removes the term from the search string and creates a new search. It's an easy way for users to refine searches using controlled vocabulary.
A search for "DNA computing" in Easy Search provides a good example of how Faceted Searching works. The results display shows 7800 hits in Compendex and Inspec, the two databases available in EI Village 2 at Vanderbilt and University of Minnesota. The first Facet is Database so clicking on the Compendex link will limit the search to just that database. Now there are 3821 records. A user can scan the list and examine some of the hits to determine what other terms might be useful. In this case, "DNA sequences" under the Controlled Vocabulary Facet looks helpful. When that link is clicked, the results list refreshes. There is now a list of three search terms, each preceded by a red X and the hit set is down to 594 records. A check of the Classification Code Facet shows another term that might be helpful, Computer Applications. Click on that and there are now four terms in the strategy and 219 hits, a much more manageable set than the original 7800.
Faceted Searching is less useful in a combined search because the terms vary across the databases. Choosing a particular term or code is essentially the same thing as limiting a search to a particular database.
The list of databases that can be combined is extensive, limited, of course, by an institution's subscriptions: Compendex, Engineering Index Backfile, Inspec, Inspec Archive, and NTIS.
There are multiple ways to save searches. Links at the top and bottom of the search results list allow users to save searches or create alerts. To use either option a user must set up an individual account. A unique option is a link to paste into an RSS (Really Simple Syndication) reader for weekly updates of searches. Users can also save individual searches from the search history screen.
OVID, DIALOG, and STN go back to 1970; EiV2 COMPENDEX provides an extra year of coverage. DIALOG and STN use command line searching, requiring knowledge of command names, field codes, limit terms, accession numbers for given years, but providing powerful search capability for those who need it. STN Easy uses pull-down menus for searching and displaying records, something that makes it easy for inexperienced searchers.
OVID doesn't require command line searching, but it could be much friendlier to novice users. Useful though it may be to automatically map terms to subject headings, new users are confused when they submit a search and don't go directly to a list of results. Just finding results in OVID can be confusing because users have to scroll down the page to find them. At first glance, it is hard to tell whether anything has changed from the search query page. Refining results is also far less obvious than in EiV2.
EiV2 COMPENDEX has the full capability of command line searching in Expert Mode, but also offers simpler searching in Easy and Quick Search modes. Refining searches and dealing with hitsets in EiV2 is uncomplicated and straightforward. Options like the Thesaurus and Browsing Indexes are probably not obvious to novice users, but they are not deeply buried. Quite a few features are included prominently on each screen without feeling busy.
Some of the other vendors offer more display formats. Nice, but not necessary. The Abstract format in EiV2 gives enough information for most users and the Detailed format takes care of those few who want more.
Faced with a choice of vendors, librarians should take all these factors into account: time period covered, ease of use for inexperienced users, availability of power features for experienced users, results display and management options, and cost. Given our experience, we have to admit we are both EI Village 2 Compendex fans.