The aim of this module is to present some reasons why the use of Statistical Process Control is so vital in industry today. It is not our intention to provide a detailed description of how to implement an SPC programme in your company, nor shall we attempt to provide a complete overview of SPC. If you would like a more in-depth guide to SPC, a larger and more detailed course is available, called An Introduction to SPC.

While there will inevitably be some overlap between this module and the main SPC course, our goal here is to show not how SPC works, but why it works (and why traditional approaches to quality control did not). We shall be focusing principally on the nature of process variation and its impact on the final quality of the product. We shall show that there is a direct relationship between the variation in a process and the quality of the output: a process which is achieving the best in quality is one which is operating on target and with minimum variation. This is a situation which can only be brought about through the application of SPC.

We have tried to present this material in a way that should be accessible both to people who are familiar with the everyday use of control charts but want to learn more about the background, and to those of you for whom this is an entirely new subject. Obviously this means that in some sections, we shall be telling you things which many of you already know, while in other sections, we may be assuming a level of knowledge that some of you do not yet have. We hope, however, that we have managed to achieve an appropriate balance, and that anyone, irrespective of practical experience will be able to follow the theory presented here.