It is becoming very important to be able to demonstrate and quantify the necessity and benefit of particular investment and operational decisions in electricity distribution systems, particularly in the context of service quality. Consequently, network performance, traditionally considered mainly from the network owners perspective, is now becoming customer driven, leading to the need to include an assessment of customers' worth of supply and the benefit they derive by system investment. This concept is at the heart of performance-based regulation. However, the development requires a framework to be created that would enable strategic decisions to be deter-mined.