With the widespread electricity regulatory reforms worldwide and the wave of privatisation, the performance of electricity industry is becoming increasingly important. This book presents the use of Data Envelopment Analysis (DEA) in the performance evaluation of Electricity Distribution Network Operators in UK. This book is motivated by the lack of electricity studies that account for quality dimensions of service in performance measurement and the inherent limitations faced by the traditional DEA models that do not reflect the trade-offs that exists in the production process. These issues are the basis of new directions taken in this book. Sophisticated DEA models with weight restrictions are developed to incorporate multiple quality measures and to reflect the technological realities of the electricity distribution production process. New quality and productivity indexes are developed to evaluate performance. This book will be especially useful to researchers, policymakers, regulators, electricity distribution operators and other organisations in various settings in need of assessing and monitoring both their productivity and quality.