What have we got to lose? The effect of controlled vocabulary on keyword searching results

Using controlled vocabulary in the creation and searching of library catalogs has evoked a great deal of debate because it is expensive to provide. Leading to this study were suggestions that because most users seem to search by keyword, subject headings could be removed from catalog records to save space and cost. This study asked, what proportion of records retrieved by a keyword search has a keyword only in a subject heading field and thus would not be retrieved if there were no subject headings? It was found that more than one-third of records retrieved by successful keyword searches would be lost if subject headings were not present, and many individual cases exist in which 80, 90, and even 100 percent of the retrieved records would not be retrieved in the absence of subject headings.