A New Classification of Variables in Design of Experiments

Abstract

The standard system factor classification of process input variables as controllable or uncontrollable does not reflect the observed structure of some processes. Specifically, some factors that are classified as controllable are actually only semi-controllable. In this paper the classic variable structure is extended to controllable, semi-controllable, and uncontrollable. This extension is proposed in an effort to deal more accurately with real world problems.

Key Words:

• Process modeling
• propagation of error

Additional information

Notes on contributors

John J. Flaig

John J. Flaig is managing director of Applied Technology a consulting, training, and software publishing company. Dr. Flaig’s special interests are in statistical process control, process capability analysis, supplier management, design of experiments, and process optimization. He holds a doctorate in engineering and technology management from Southern California University, a master’s degree in mathematics from the University of California, and a bachelor’s degree in mathematics and economics from California State Polytechnic University. He is a Fellow of the American Society for Quality.