Searchers' selection of search keys: II. Controlled vocabulary or free-text searching

Searching with descriptors from controlled vocabularies complements free-text searching with textwords. The case study method provided data about the manner in which the two types of search keys interact through: (1) observation of 47 professional searchers performing their job-related searches; and (2) analysis of verbal and search protocols, denoting reasons for the selection of each search key and for each search modification. Results show that searchers used thesauri and indexing when it was of satisfactory quality and available to them, and that these and other database-related reasons were the most influential in search-key selection. Further, having to perform a multidatabase search induced the use of textwords without consulting a thesaurus. There is a need for high quality thesauri which are easily available and for mechanisms, such as switching languages, to aid in multidatabase searches.