Google has made a big impact on college campuses recently with its release of a new specialty search engine, Google Scholar (also known by the nickname Schoogle).

Sometimes called vertical search engines, tools like Google Scholar limit themselves to certain types of information or certain subjects. In the case of Scholar, Google aims to cover scholarly information from published journals, institutional repositories, preprint services, theses and dissertations, and technical reports. Like the famous PageRank^TM system they pioneered in regular Google, Scholar analyzes the popularity of a work according to the number of times it has been cited, and displays search results showing the most-cited references first.

Unfortunately, Scholar is still very much a BETA release. Google is playing coy with information about its coverage and completeness, and output can't be managed easily. While it's fun to play with, Scholar is not yet a candidate for serious searching.

AISR recently subscribed to Elsevier's Scopus database, which includes cited reference analysis for articles back to the mid-1990s. Covering over 14,000 journals across a broad spectrum of sciences, Scopus also includes all MEDLINE and EMBASE records. For the years it covers, Scopus is just as effective at cited reference searching as the long-established Science Citation Index/Web of Science (SciSearch WoS), while Google Scholar runs a very distant third.

The table below compares citations for papers from three Jefferson authors. Note that Scopus and SciSearch (WoS) results are fairly close compared to Google Scholar.

Scopus is also under development - Elsevier expects to extend its coverage of cited references further back in time, competing directly with Web of Science. But for current years, Scopus is your best choice, hands down.

It's going to be interesting to watch these products develop over the next few years. With luck, the research community will benefit from all the competition.

• Google Scholar
• Scopus