Greater reliance is being placed upon probability methods in the determination of generating capacity requirements. Regardless of the application method, the basic need is an adequate record of operational performance as a guide to proper outage rates and durations. Herein is described a method for collection, validation, and analysis of outage data to meet the requirements of a wide range of methods. Through computer application, accurate up-to-date data are provided to assist in solving the problems relating to system design and expansion.