Based on information solicited from database producers which had files publicly available on SDC and/or Lockheed, this study is intended to help searchers assess available database support materials with regard to their cost, format, depth, and purpose. The eight assumptions addressed cover the following areas: (1) the amount of reference material provided by for-profit database producers vs. the amount provided by non-profit producers; (2) the availability of free or low-priced materials from government database producers; (3) the relationship between non-profit producers and professional societies, and its effect on the amount of material available; (4) the relationship between the technical complexity of the file and the amount of material offered; (5) the percentage of producers offering source lists, classification code lists, and vocabulary lists; (6) the need for vendor-produced material in lieu of search-specific information provided by producers; (7) the usefulness of free items; and (8) system-produced manuals vs. file-specific information from producers. Investigation methods of the study are outlined, and charts identify the databases reviewed, the number of reference materials offered by three types of database producers, search aid availability, reference material content, and free items. A bibliography is provided. (FM)