On recommending

The core of any document retrieval system is a mechanism that ranks the documents in a large collection in order of the likelihood with which they match the preferences of any person who interacts with the system. Given a broader interpretation of “recommending” than is commonly accepted, such a preference ordering may be viewed as a recommendation, made by the system to the information seeker, that is itself typically derived through synthesis of multiple preference orderings expressed as recommendations by indexers, information seekers, and document authors. The ERIn (Evaluation–Recommendation–Information) model, a decision-theoretic framework for understanding information-related activity, highlights the centrality of recommending in the document retrieval process, and may be used to clarify the respects in which indexing, rating, and citation may be considered analogous, as well as to make explicit the points at which content-based, collaboration-based, and context-based flavors of document retrieval systems vary.