The objectives of the study were to conduct a series of observations and experiments under as real-life a situation as possible related to: (i) user context of questions in information retrieval; (ii) the structure and classification of questions; (iii) cognitive traits and decision making of searchers; and (iv) different searches of the same question. The study is presented in three parts: Part I presents the background ot the study and describes the models, measures, methods, procedures, and statistical analyses used. Part II is devoted to results related to users, questions, and effectiveness measures, and Part III to results related to searchers, searches, and overlap studies. A concluding summary of all results is presented in Part III.
introduction
Problem, Motivation, SignificanceUsers and their questions are fundamental to all kinds of information systems, and human decisions and humansystem interactions are by far the most important variables in processes dealing with searching for and retrieval of information. These statements are true to the point of being trite. Nevertheless, it is nothing but short of amazing how relatively little knowledge and understanding in a scientific sense we have about these factors. Information retrieval *Work done under the NSF grant IST85-05411 and a DIALOG grant for search time.'Present address: Kent State University, Kent, Ohio *Present address: Dyke College, Cleveland, Ohio Received February 5, 1987; accepted March 19, 1987. 8 1988 systems, expert systems, management and decision information systems, reference services and so on, are instituted to answer questions by users-this is their reason for existence and their basic objective, and this is (or at least should be) the overriding feature in their design. Yet, by and large and with very few exceptions (see ref. 1) the basis for their design is little more than assumptions based on common sense and interpretation of anecdotal evidence. A similar situation exists with online searching of databases. While the activity is growing annually by millions of searches it is still a professional art based on a rather loosely stated set of principles (see ref.2) and experience. While there is nothing inherently wrong with common sense, professional art, and principles derived from experience or by reasoning, our knowledge and understanding and with them our practice would be on much more solid ground if they were confirmed or refuted, elaborated, cumulated, and taught on the basis of scientific evidence.Since 1980 a number of comprehensive critical literature reviews have appeared on various topics of information seeking and retrieving, among them reviews of research on It is most indicative that an identical conclusion appears in every one of these reviews despite different orientation of the review and different backgrounds of the reviewers. They all conclude that research has been inadequate and that more research is needed. In the words of Belkin and Vickery: '1 . . . research has not yet provided a satisfactory solution...
