Mikel J. Harry - Practitioner′s Guide to Statistics and Lean Six Sigma for Process Improvements

Copyright 2010 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data:

Practitioners guide for statistics and lean six sigma for process improvements/Mikel J. Harry [et al.].

p. cm.

Includes index.

ISBN 978-0-470-11494-0 (cloth)

1. Process control-Statistical methods. 2. Six sigma (Quality control standard) 3. Statistics-Data processing. I. Harry, Mikel J.

TS156.8.P72 2009

658.50727--dc22

2009034002

PREFACE

Top management is supposed to be a tree full of owls - hooting when management heads into the wrong part of the forest

Robert Townsend, business writer.

INTRODUCTION

At times the practitioner might wonder why many people go into Lean Six Sigma and statistics. Is their DNA different? What do practitioners of Lean Six Sigma do, practice, or believe in? At a time when success depends on satisfying the need for developing quantitative skills and reasoning abilities, the mystique surrounding Lean Six Sigma persists. Practitioners Guide to Statistics and Lean Six Sigma for Process Improvements shows some of the payoffs for working with the fundamental concepts of statistics combined with the methodology of Lean Six Sigma. The areas of discussion are real. Most of the situations that the practitioner encounters in the book are based on hands-on experience. The goal is for the practitioner to enjoy solving business problems and have fun while doing it. The reader is not expected to become a statistician; it is understood that the practitioner might not remember in a year or so most of the techniques presented here. However, this is not the goal; what we would like to see is that you solve some of your businesss most important problems and gain appreciation for the how, the when, and the why. Lean Six Sigma is not about complex formulas and equations; it is about graphical, visual, and simple analytical methods. It is about looking with a method at a business problem and its processes and then creating graphical representations to work with in order to solve those business problems and improve the business processes for cost effectiveness. This is what counts.

We begin the preface of this first edition of Practitioners Guide to Statistics and Lean Six Sigma forProcess Improvements with a question that most Lean Six Sigma practitioners have been asking. Just what are statistics and Lean Six Sigma used for? For application purposes, Practitioners Guide to Statistics and Lean Six Sigma for Process Improvements is our response to this question, and an attempt to fill this need. This book represents a combined effort to create excitement, interest, curiosity, and desire in the non specialist for cost reduction and value-centric thinking that is based on the fact that errors or mistakes in process execution are directly linked to many of the economic fundamentals that underlie a business. Of course, such fundamentals include things like cycle time, work-in-process, labor cost, and non value activities that consume time and resources, to mention only a few. In this book, we attempt to create a strong desire for reading Practitioners Guide to Statistics and Lean Six Sigma forProcess Improvements, by knowing that each of our readers will understand that reducing defects and defect opportunities directly reduces cycles-time, work-in-process, labor, scrap, rework, and equipment utilization. Our efforts have been guided by Thomas Jeffersons notion that an enlightened citizenry, in which practitioners, having acquired a broad knowledge of topics, can then exercise sound judgment in making business and economic decisions. Managers who have learned this material should agree that many of their past management practices and quality programs might need some updating.

The book is designed to introduce Lean Six Sigma practices and statistics. It is also intended to serve as a reference for the Lean Six Sigma community. We envisioned that our readers come from multiple communities executive, management, and Lean Six Sigma practitioners and possess diverse education, work experience, and skills. This aim required that the material be presented at several different levels of understanding. Recognizing that practitioners learn in a variety of ways, we have provided alternative approaches to help readers visualize and interpret common types of business problems. Thus, this book contains more than 1000 figures to explain arithmetic, algebraic, statistics, and Lean Six Sigma concepts and results. In writing this book, a struggle with the traditional teaching method in which authors present a problem and immediately solve it was encountered. Practitioners Guide toStatistics and Lean Six Sigma for Process Improvements believes that an important part of problem solving is to encourage reflection by the practitioner before action. Thus, examples covering fundamental concepts offer hints, rather than firm directions, to guide the readers choice of tools and methods.

The chapters of the book are divided into two different groups applications and theory. Applications are emphasized in Chapters 19, 15, 21, 22, and 23, while theory is emphasized in Chapters 1014, 1620 and 24. The chapter sequence 124 is a natural one for mastering all of the material. On the other hand, someone who has interest in the material might begin with the summary or overview sections of the first six chapters.