Due to the rising cost of operation, librarians in recent years are increasingly being called upon to provide more vigorous justification for their budgets. As a result, new managerial techniques are being applied to the evaluation of library services. In evaluating library services we must consider the efficiency of the library’s internal operation and its effectiveness in implementing the goal of service to users. The efficiency, effectiveness and benefits of a library can frequently be determined on the basis of formulas adopted for the specific facet of library services-effective hours of use, circulation per user, collection, use of equipment and facilities in the library, and reference service.