Chapter 7: Preparing for Control Charts

Preparing for control charts is critical. Decisions made at this stage often determine whether or not the charts will succeed. Without careful planning and concern for these early decisions, control charts often become useless and meaningless. Specifically, this chapter will cover some preparation steps and awareness as to what is needed to have a successful control charting strategy for the process.

OVERVIEW

We are about to undertake the analysis of a process via a control chart. Our intent is to evaluate the process and to distinguish the common from the special variation. This sounds very easy; however, in practice it is very difficult. The reason for this difficulty lies in lack of appropriate and applicable preparation, not only for the process but also for the person who is doing the evaluation.

Things of concern before the actual control charting process include the following:

• The kind of data necessary for the analysis

• The kind of sample used in the analysis

• The frequency of the sample

• The kind of control chart used