Classification of major event days

This paper explores the basis, need, and benefit of classifying reliability performance relative to major events. Today, many internal and external goals are set based on reliability performance. Internal as well as external comparison is difficult to make due to variations in weather, collection methods, and a plethora of other variables. The Working Group on System Design has developed a statistics based methodology that classifies reliability data into normal and major event days. After classification, analysis can be performed on each data set using separate processes to arrive at sound business decisions and to make internal comparisons possible. This paper describes the newly developed methodology, the "beta method".