Effects of search experience and subject knowledge on the search tactics of novice and experienced searchers

This study investigated the effects of subject knowledge and search experience on novices' and experienced searchers' use of search tactics in online searches. Novice and experienced searchers searched a practice question and two test questions in the ERIC database on the DIALOG system and their use of search tactics were recorded by protocols, transaction logs, and observation. Search tactics were identified from the literature and verified in 10 pretests, and nine search tactics variables were operationalized to describe the differences between the two searcher groups. Data analyses showed that subject knowledge interacted with search experience, and both variables affected searchers' behavior in four ways: (1) when questions in their subject areas were searched, experience affected searchers' use of synonymous terms, monitoring of the search process, and combinations of search terms; (2) when questions outside their subject areas were searched, experience affected searchers' reliance on their own terminology, use of the thesaurus, offline term selection, use of synonymous terms, and combinations of search terms; (3) within the same experience group, subject knowledge had no effect on novice searchers; but (4) subject knowledge affected experienced searcher's reliance on their own language, use of the thesaurus, offline term selection, use of synonymous terms, monitoring of the search, and combinations of search terms. The results showed that search experience affected searchers' use of many search tactics, and suggested that subject knowledge became a factor only after searchers have had a certain amount of search experience. © 1993 John Wiley & Sons, Inc.