We live in an age when a great deal of information comes to us in the form of numbers. Indexes, polls, leading indicators, scientific studies, government statistics and medical reports attempt to disseminate knowledge based on ever increasing amounts of data. According to Dr. Donald J. Wheeler, a nationally renowned author of industrial and business applications of statistics, the majority of managers, workers, accountants and to a lesser extent engineers and scientists have no real understanding of the role variation plays when digesting data to extract useful information. From a quality improvement perspective, this statement is profound since improvement efforts always center on the interpretation and analysis of data. Dr. Wheeler purports that through the application of sound measurement methods and statistical analysis, organizations can optimize the processes and systems designed to effectively accomplish and manage work.
Variation is random fluctuations and miscellaneous changes inherent in every part of every process.
While we readily acknowledge and accept the existence of variation in everyday life, many organizations are just beginning to recognize the degree to which variation occurs throughout the workplace. It is intrinsic to all systems and processes and in the data we collect to monitor and measure their performance. Once collected the data must be filtered for the purpose of interpretation and analysis. Without an appropriate approach to interpret data there is no means to extract the knowledge the data may contain. Two common approaches used to interpret data are comparison to specifications and comparison to averages.