The blog post

TODAY marks the centennial of one of the most significant innovations in quality management: the control chart. 🎂 🎉 🎆

In the early 1920s, Walter A. Shewhart, working at Bell Labs, recognized the need for a statistical method to monitor and control manufacturing processes.

On May 16, 1924, Shewhart created the first “control chart,” a tool that distinguished between common cause variation (inherent in the process) and special cause variation (due to specific, identifiable factors). This simple yet powerful distinction laid the foundation for modern statistical process control (SPC). Control charts were dubbed “Process Behavior Charts” by Donald J. Wheeler Ph.D.)

The latest and greatest of the control charts is the “XmR Chart” — as Wheeler wrote about in Understanding Variation and I wrote about in Measures of Success (a book that has a foreword written by Wheeler).