Buy or copy? A library operations research model

The problem of how much of a branch library's budget shoud be spent on acquisition of new material as opposed to holding capital in reserve to photoduplicate material at the main library upon demand is presented. A mathematical model is constructed and discussed in detail, and a solution procedure basen on a dynamic programming approach is developed. Several photoduplication policies are considered, modeled, and compared. An example problem is presented to show how the formulas work. Thus a library problem representative of the larger problems of library networks is developed further as an example of library operations research.