Relevance is a, if not even the, key notion in information science in general and information retrieval in particular. This two-part critical review traces and synthesizes the scholarship on relevance over the past 30 years or so and provides an updated framework within which the still widely dissonant ideas and works about relevance might be interpreted and related. It is a continuation and update of a similar review that appeared in 1975 under the same title, considered here as being Part I. The present review is organized in two parts: Part II addresses the questions related to nature and manifestations of relevance, and Part III addresses questions related to relevance behavior and effects. In Part II, the nature of relevance is discussed in terms of meaning ascribed to relevance, theories used or proposed, and models that have been developed. The manifestations of relevance are classified as to several kinds of relevance that form an interdependent system of relevancies. In Part III, relevance behavior and effects are synthesized using experimental and observational works that incorporated data. In both parts, each section concludes with a summary that in effect provides an interpretation and synthesis of contemporary thinking on the topic treated or suggests hypotheses for future research. Analyses of some of the major trends that shape relevance work are offered in conclusions.
Prologue to Part III: How It Is Connected and What This Work Is All AboutTo provide a continuation from the preceding Part II, a few basic descriptions about this work are repeated.As stated in the Preface to Part II, in 1975 I published a review about relevance under the same title, without, of course, "Part I" in the title (Saracevic, 1975). There was no plan then to have another related review 30 years later-but things happen. The intent of the 1975 work was "to explore the meaning of relevance as it has evolved in information science and to provide a framework within which various interpretations of relevance can be related" (Saracevic, 1975, p. 321).Building on the examination of relevance in the preceding (1975) review, this work (2007) follows the travails of relevance in information science for the past 30 years. It is an update. The aim of this work is still substantially the same: It is an attempt to trace the evolution of thinking on relevance in information science for the past three decades and to provide an updated, contemporary framework within which the still widely dissonant ideas on relevance might be interpreted and related to one another.The organization of the present review, offered in two parts, addresses the questions related to relevance nature, manifestations, behavior, and effects. Following the Introduction and a Historical Footnote, the preceding Part II (this issue, pp. 1915-1933) started with a general section on the nature of relevance by synthesizing its meanings, following with sections on theories and models of relevance that are, in effect, further elaborations on the nature of relevance. Part ...
