The purpose of our study was to provide more comprehensive information on factors associated with over-order payments. We hope this information will clarify some of the issues surrounding over-order payments and assist in public policy formulation. This study provides more comprehensive information because: (a) the scope of the study included all orders (b) the data were for a 13 year time period (1965 through 1977), and (c) the study included factors which might influence over-order payments that have not previously been analyzed.