Effects of conceptual instruction on subject-searching performance in a computerized library catalog

Previous research in online catalog search behavior has shown that users have difficulty in performing subject searches. To aid searchers, controlled vocabularies have been added to online catalogs as searchable files. The present study investigated whether written instructions explaining conceptual components of subject-searching would improve search performance. Subjects (N = 34) were randomly assigned to one of two groups, only one of which received written instructions on subject searching. The instruction was based on a theory that users develop more accurate mental models of computing systems if certain actions of the computer are made more explicit. Subjects performed 6 subject-searching tasks (3 easy, 3 difficult) on a menu-driven, computerized library catalog. Online help was available during the search tasks. Search behavior was recorded by a microcomputer functioning as a remote terminal. Performance measures included: task score, task time, use of the controlled vocabulary, and number of screens viewed. A questionnaire following task completion asked subjects to rate the difficulty of subject searching. In addition, exit interviews assessed subjects' conceptual understanding of search procedures. Discriminant analysis showed that the instruction group received higher task scores and used the controlled vocabulary more often than the no-instruction group. A greater number of subjects in the instruction-group could explain the difference between the bibliographic records file and the controlled vocabulary file. In general, subjects did not rate subject-searching as difficult and attributed their task failures to a failure of the library's collection, rather than to their own searching errors. Subjects in both groups cited the card catalog as the source of prior knowledge which was the most helpful to them in performing the searches. These results indicate that a conceptual model provided through written instructions can promote understanding beyond that provided by online help alone, leading to improved subject-searching performance.