This paper describes a two-year study by the British Library Research and Innovation Centre that examined the potential of self-assessment for public library services. The approaches that formed the basis for the investigation were the Business Excellence Model, the Quality Framework, and the Democratic Approach. Core values were identified by library managers, including customer focus, equity in service, an open system, public participation, visible and visionary leadership, employee development, involvement and satisfaction, continuous improvement, management by fact, partnership development, consistency of purpose, process management, public responsibility, and stakeholder consideration. The model that emerged, the Library and Information Sector Improvement Model (LISIM), was sent out for feedback in order to produce a tool-kit and training pack that would achieve wide acceptance. A table summarizes the principles that underlie the LISIM, including a general principle, management principles (consistency of purpose, continuous improvement, benchmarking, and management by fact), and human factors (visible and visionary leadership, stakeholder consideration, and employee development/involvement/satisfaction). The following stages required for any successful change management activity are outlined: (1) identify the role of self-assessment; (2) commit to the process; (3) identify the self-assessment team; (4) choose the self-assessment model/approach; (5) piloting/training/planning; (6) undertake the self-assessment/manage the process; (7) identify priorities for improvement/plan actions/implement actions; and (8) review. (Contains 10 references.) (MES)