Describes how library decision-making was enhanced by a systematic study of patrons, services, and effectiveness based on the concept known as performance measures for public libraries. Improvements in the data gathering and analysis techniques are noted; also provided are survey instruments, examples of selected revised forms, and references. (SW)

An extensive study was conducted to determine whether California's Public Library Services Act had succeeded in its goal of improving and extending library service through the establishment and funding of library systems. The comprehensive study involved field interviews at all 20 systems; a review of system documents; a survey of reference…