The Laney p’ Control Chart is an exciting innovation in statistical process control (SPC). The classic control charts for attributes data (p-charts, u-charts, etc.) are based on assumptions about the underlying distribution of their data (binomial or Poisson). Inherent in those assumptions is the further assumption that the “parameter” (mean) of the distribution is constant over time. In real applications, this is not always true (some days it rains and some days it does not). This is especially noticeable when the subgroup sizes are very large. Until now, the solution has been to treat the observations as variables in an individual’s chart. Unfortunately, this produces flat control limits even if the subgroup sizes vary. David B. Laney developed an innovative approach to this situation which has come to be known as the Laney p’ chart (p-prime chart.) It is a universal technique that is applicable whether the parameter is stable or not.
About Your Presenter, David B. Laney
David B. Laney worked for 33 years at BellSouth as Directory of Statistical Methodology. He is a pioneer at BellSouth in TQM, DOE, and Six Sigma. David’s p-prime chart is an innovation that is being used in a wide variety of areas. It is now included in many statistical applications, such as Minitab and SigmaXL. David is enjoying retirement with his family in the Birmingham, Alabama area.
Date: Wednesday, September 28, 2011
Click here to view a video recording of David’s webinar.