Proposes and explains a modification of the mixed Poisson model for library circulations which takes into account the periods when a book is out on loan and therefore unavailable for borrowing. Highlights include frequency of circulation distributions; negative binomial distribution; and examples of the model at two universities. (Contains 34…

The relationship between the library and its patrons is damaged and the library's reputation suffers when returned items are not checked in. An informal survey reveals librarians' concern for this problem and their efforts to combat it, although few libraries collect objective measurements of errors or the effects of improvement efforts. Brigham…