Statistical process control charts, aka Shewhart control charts, are introduced in our Green Belt course. At the Black Belt level, students are tasked to develop control charts for the primary Y variable that is to be the focus of improvement during the Define phase of their Black Belt project. Before we can rely on the […]

# Category Archives: Six Sigma

Data that follow a distribution that is either not symmetric or that is symmetric but not bell shaped are said to be non-normal. A common misconception among students is that all data should be normally distributed, and that there is something inherently wrong if their data is not normally distributed. In fact, data is not […]

Black Belt students are exposed to Design of Experiments (DOE) in their classroom training, but in my experience very few of them actually apply the technique while completing a project to earn their Black Belt certificate. One of my students recently completed a project that made excellent use of a Designed Experiment, and his company […]

Our Yellow Belt course includes an assignment where students are required to write an operational definition for measuring something. An operational definition, when applied to data collection, is a clear, concise and detailed definition of a measure. The need for operational definitions is fundamental when collecting all types of data. Here is the text of […]

The entire country watched in disbelief last week as a United Airlines passenger was forcefully pulled off an overbooked flight to give room for crew members. The passenger had a valid ticket and boarding pass and was already in his assigned seat when he was dragged off the plane. How could this happen and why? […]

We often need to improve the performance of a complex system using Six Sigma. In this article we will discuss how to use simulation to our benefit. We first define the problem as a requirement that is not being met. We collect data about the extent of the problem and the factors that influence the […]

In our Six Sigma courses we make extensive use of Minitab statistical software. Minitab is an extremely comprehensive and powerful software package. At the same time author Milton Rosenau provided this caution when he said “(Software)…is also a trap for the unwary.” When evaluating the output of a piece of software such as Minitab, we […]

One of the first assignments in our Black Belt course deals with the origins of the continuous improvement approach that we know today as Six Sigma. Many students are surprised to learn that the body of knowledge and the tools and techniques have been evolving for well over 100 years. This article is the fourth […]

One of the first assignments in our Black Belt course deals with the origins of the continuous improvement approach that we know today as Six Sigma. Many students are surprised to learn that the body of knowledge and the tools and techniques have been evolving for well over 100 years. This article is the third […]

One of the first assignments in our Black Belt course deals with the origins of the continuous improvement approach that we know today as Six Sigma. Many students are surprised to learn that the body of knowledge and the tools and techniques have been evolving for well over 100 years. This article is the second […]