It is shown that Trueswell's empirical 80/20 rule arises from type of stochastic model for library loans presented by Burrell and Cane. Particular attention is paid to previously suggested uses of rule in identifying "core collection" for library noting that length of time period is of crucial importance. (20 references) (EJS)

Argues that library book circulation is a binomial rather than a Poisson process, and that individual book popularities are continuous beta distributions. Three examples demonstrate the superiority of beta over negative binomial distribution, and it is suggested that a bivariate-binomial process would be helpful in predicting future book…

Correlation structure of the Burrell and Cane mixed Poisson model for library loans with aging is presented and illustrated by data from University of Sussex. The approach is compared and contrasted with that originally formulated by Morse and recently reevaluated by Beheshti and Tague. Directions for future investigations are suggested. (Author)

Two models of library circulation, the Markov model and the mixed Poisson Model, are applied to circulation statistics from the University of Saskatchewan. Goodness-of-fit tests indicate that neither model fits the data; in both cases, the set of noncirculating items is larger than that predicted by the model. (Author/LRW)