A research group at the Wharton School, University of Pennsylvania, worked on the development of a system to provide the required statistical information for effective management and decision making in university and large public libraries. A management science approach was used. Library objectives, standards, and performance criteria were examined, with emphasis on their operational definition. A framework for planning and decision making was created, dividing library activities into 17 basic functions and isolating the inputs and outputs of each. Library quantitative models were summarized and classified according to their application to library decisions and functions. A model management information system was detailed in terms of characteristics and structures, data requirements for library performance measures and program indicators, and benefit-cost criteria for system elements. Finally, projections were made beyond the individual library to some of the factors involved in effective management information systems for libraries at the system, state, and national level. (Author/SL)