Making Sense of Data: SPC for the Service Sector

Citation

Narasimhan, K. (2004), "Making Sense of Data: SPC for the Service Sector", Managing Service Quality: An International Journal, Vol. 14 No. 2/3, pp. 258-259. https://doi.org/10.1108/09604520410528680

The need for continual improvement in services even in manufacturing industries has been recognized. However, one barrier to its wide implementation has been the tendency to link concepts such as statistical process control only to the production of goods and not to the offering of services. This book by Wheeler shows very effectively, with appropriate examples, how making sense of data is equally important and can be effected using techniques used in manufacturing.

Dr Wheeler is a Fellow of the American Statistical Association and has worked with Dr W. Edwards Deming and has periodically assisted him with his seminars. He has teaching experience and has provided consultancy for firms in both manufacturing and the service industry. He has also authored articles and books on process‐control related topics.

The book comprises 19 chapters by the author, an “Afterword” on the germ theory of management by Dr Myron Tribus, a consulting engineer specializing in quality management, and an ex‐director of the Center for Advanced Engineering Study at Massachusetts Institute of Technology, USA. The text is supported by 233 figures, six reference tables, 62 data tables, 130 examples and case histories, glossary of symbols, appendices, bibliography, and index.

In the very short chapter 1, the term quality is defined and it is emphasized that it is not enough to specify what needs to be accomplished but it is essential to specify how the objective should be accomplished and how to determine the progress towards that goal. Chapter 2 deals with the twin techniques of constructing accurate flow charts to visualize processes and cause‐and‐effect diagrams for representing the relationship between problems and their sources, using participation and brainstorming.

Chapters 3 to 6 are respectively devoted to the topics of collecting good data over time, communicating that data in a clear and concise manner using tables, graphs and charts, the efficacy of using simple appropriate charts rather than complicated and unwieldy charts, and summarizing numerical data using measures of location (mean and median) and spread (range and deviation).

Chapters 7 to 9 deal with process behavior charts for identifying predictable (routine) and unpredictable (exceptional) variations and using them effectively for continuous improvement by separating potential signals from probable noise. In chapter 10, the principles for creating good process behavior charts and the pitfalls to avoid are succinctly explained; and in chapter 11, the logic underpinning the process behavior charting technique is covered. In chapter 12, titled “Avoiding man‐made chaos”, Donald very ably demonstrates the pitfalls of using descriptive statistics without analysis and shows how to filter out noise to detect signals to ensure that efforts of improvements are not misdirected. Also introduced in this chapter are the construction of simple trend lines and trended limits for a time‐series plot.

Chapters 13 to 15 deal with the differences between measurements and counts of items and events; aggregating and disaggregating data and problems encountered; how to collect good count data, chart the count data, and use them effectively. In chapter 16, the advantages, restrictions and issues surrounding average and range charts are first introduced with the aid of examples from manufacturing and then the application of these charts in services is illustrated. In chapter 17, the topic of smoothing out seasonal data using moving averages is covered. Chapter 18 is devoted to the topic of deseasonalizing data containing strong seasonal components. In chapter 19, titled “The learning way”, Donald provides two extended examples to illustrate how the plan‐do‐study‐act cycle has been used to build continuous improvement into the processes in a mail order firm, and by the quality circle at a night club in Osaka, Japan.

Most of the chapters include exercises (43 exercises with answers at the end of the book) to reinforce the concepts and methods covered in the chapters. I find the book extremely useful as a teaching aid on courses ranging from undergraduate and MBA courses to executive training programs. It would also be most useful as a reference text for those interested in effecting and reporting continuous improvement programs.