Book Review: “Introduction to Statistics For Metrology”, by Crowder, Delker, Forrest, and Martin.

Paul Reese Collin Delker Henry Z. Greg Cenker

If you find yourself wanting to cross a big threshold and buy your first Metrology reference book, I have never seen or heard of a better candidate than this one. It will return your investment for many years. Let’s focus on:

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Money: I have been benefitting from Greg Cenker’s leadership for decades and this is another positive example. Greg recommends this book, but when I looked up the price of the hardback version, I told myself “no effing way"! Then the reviews on Amazon convinced me to change my mind. My next stop was to consult with the Chancellor of the Exchequer. She said to go ahead because Metrology has become my main focus since my retirement.

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But that’s just me.? Having finished reading it, I can list several good reasons why you, on the other hand, are going to benefit from buying and using this book.

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·???? Attitude. The goal of some academic authors appears to be to prove that they are smarter than any of their students, and most of their colleagues. This can be effective in a college setting in which the professor requires their own book for a course that they are teaching. Sometimes Metrology writers fall into this same mindset. I suspect, for example, that this infected the Technical Committees responsible for writing the ISO’s GUM (1993). But in this case, these four authors managed to either dodge this trap from the start or to edit it out completely before they published in 2020. Instead, they display an unfailingly generosity toward their readers in three distinct ways. 1) They demonstrate generosity most directly by taking the extra care and effort necessary to write very clearly. Then they go further by 2) freely citing a ton of sources at the end of each chapter in case you need to dig further to understand, explore and then solve your particular problem. 3) Lastly, they organize and execute this book so clearly that they never need to “Appeal to Authority”. This means that they never resort to using the existence of any previously established source as the reason why we should blindly buy their arguments. Over time, it will be insufficient to use “because it's in the GUM” as an argument for any position. With every new topic that they introduce in the book, the authors start simply and build logically from there.

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·???? Problem solving. To me, the very practical orientation of this book reminds me of the kind of “circuit cook book” that people write to support electrical circuit designers searching for a solution to a distinct and sometimes unique electrical circuit design problem. In its 11 Chapters, this book approaches a very wide range of topics that involve measurement people and Metrologists on a daily basis. Why not look at the Table of Contents for yourself?

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·???? Sensible organization. Have you ever noticed how very easy it is for writers to wander off into very abstract Measurement or Statistical Theory and never be seen again? These four authors are plenty smart. One of them went to MIT for a BS, then a Masters, and then stuck around for a Ph. D. But they never let that go to their heads. Each chapter starts off simply and clearly and then develops one or more interesting branches as they appear in front of us. This simplicity and clarity makes it easy for the reader to decide whether to skim any Chapter or dive right to the bottom including following their links to further resources and even doing the exercises. Their writing draws us into new areas that might pleasantly surprise us.

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·???? Modern. I mean “modern” compared to the context, conditions, and viewpoints that created the GUM 31 years ago. In 1993, the GUM was a superb synthesis and a technical triumph that allowed a very small but worldwide group of advanced pros to produce formal estimates of just about any process Measurement Uncertainty. But the GUM appeared in a period when “hand calculations” were just about the only route to producing an actual uncertainty estimate. Things have changed so much that the Exercises at the end of the chapters often ask the reader to use their “favorite programming language ” to answer a question. These simply didn’t exist in 1993. Hint: Download (FREE) and start using “R” or an equivalent or accept that Metrology is in the midst of leaving you in its wake. “R” is free, powerful and easy to download. Hint: Or try SUNCAL, free and homegrown at Sandia Labs. We can all agree that we will be seeing more and more software in the future of Metrology. This book makes very frequent references to the very broad software environment within which we approach any measurement topic. By "broad" I mean to include the point of view of both users or code writers.

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·???? We are on a route to Heaven, but we haven’t arrived quite yet. Early in the book, the authors contrast the “Error Approach” and the “Uncertainty Approach”. The “Error Approach” implicitly assumes the existence of a philosophical object called a “true value”. Yet all attempts to render this value as a measurement data point will always have an error element attached in a way that we cannot remove, or ever counteract it. In contrast, the VIM (ISO technical vocabulary of measurement terms), the GUM, along with the authors of this book, emphasize, instead the “Uncertainty Approach”. This big change in emphasis, accelerated by the appearance of the GUM, moves us forward by trading in the impossibility of ever getting a glimpse of a “True Value” and replacing it with the practical benefits that come from being able to execute a careful, formal, globally recognized estimate of measurement uncertainty. Does the GUM still refer to a “True Value”? Hells yes! Does this excellent book commit the same “sin”? Same answer. We use language, but we should never forget that language uses us at the same time. Our calibration and Measurement professions are unlikely to completely reject the concept of a “true value” until we manage as a group to replace it with something more useful and powerful. What our measurement customers, bless their hearts, will be doing in the meantime is out of our control!

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I am glad that Greg pointed me in the direction of this book. I am also very happy to see the very significant progress that we have made in Metrology since 1993, and I hope that you all are too. This book represents real, solid improvement in our practice and not marketing hype from a huge text book publisher. (I was however, fascinated to see that Springer printed my copy “on demand” and assembled my copy just four days before it arrived on my doorstep.)

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Last words! If you are stuck, try thinking of this purchase not as an object but an investment in your career. To shrink all this great advice into four words: Get this book, NOW!