This paper discusses the importance of end-use load shape data for utility integrated resource planning. It summarizes leading utility applications and reviews progress to date in obtaining load shape data. The review describes major end-use data development efforts, origins of and current state of the art in each topic area are discussed. Major conclusions of the paper are: (1) Current metering projects are producing valuable data that have broad applicability to other service territories; (2) load shape estimation techniques have matured sufficiently to represent reliable tools for planning. Finally, the paper outlines directions for future research by arguing for closer coordination between future metering efforts and load shape estimation technique development and, in fact, suggests that the most promising avenue for cost-effective development of end-use load shape data is an optimal combination of data transfer, simulation, statistical analysis, and end-use metering.