A user is mapped into a user type and then the appropriate group data objects are generated and their labels displayed to the user for selection. Selection generates the extractors from each database for that user type in that group data object. Three medical databases clustered yielded eight concept classes and multiple user objects were created. Tests showed varied query production in the same concept classes for the various groups . After reviewing the literature of evaluative web search tool research, Nicholson replicates the 1996 Ding and Marchionini search service study ten times during the Summer of 1998.
Previous work finds replication yields significantly different results over time.
The first twenty pages returned by Infoseek, Lycos, Alta Vista and Excite for the five queries were examined and ranked between 0 and 5 for relevance. Differing engine rankings for each replication are the rule. Using two queries, one designed to have a stable answer and another a dynamic answer over time, the four systems were tried again on five successive weeks. New pages appearing in the first 20 pages in each successive week were counted, as were pages that changed ranked position. Both queries showed considerable change week to week.