Scouting the perimeters of unobtrusive study of reference

This paper reviews the origins of the unobtrusive method of evaluating reference service in libraries, setting the method in a theoretical and organizational context. Drawing examples from the more than sixty studies performed in the past twenty years, limitations and strengths of the unobtrusive methods are explored. It is concluded that the technique, perhaps the most rigorous method of evaluating reference service, is useful for its client-centered perspective and its non-reactivity. It deserves not only continued use but continued development as a method of evaluation.published or submitted for publicatio