Content by Donald J. Wheeler

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Donald J. Wheeler
Last month we provided an operational definition of when measurement systems are equivalent in terms of bias. Here we will look at comparing the within-instrument measurement error between two or...
Donald J. Wheeler's picture
Donald J. Wheeler
As soon as we have two or more instruments for measuring the same property the question of equivalence raises its head. This paper provides an operational definition of when two or more...
Donald J. Wheeler's picture
Donald J. Wheeler
Managers the world over want to know if things are “in control.” This usually is taken to mean that the process is producing 100-percent conforming product, and to this end an emphasis is placed upon...
Donald J. Wheeler's picture
Donald J. Wheeler
With the click of your mouse you can turn a list of values into a bubble plot. No thought or effort is required. Simply sit back and let the software gods do the heavy lifting of transforming...
Donald J. Wheeler's picture
Donald J. Wheeler
Story update 1/15/2019: Thanks to the sharp eye of Dr. Stan Alekman, who spotted an inconsistent value in figure 2, I discovered an error in the program used to construct the table of critical...
Donald J. Wheeler's picture
Donald J. Wheeler
Process behavior charts are the interface between your data and your brain. But you have to begin by making a choice about which type of chart to use. You can either plot the individual values...
Donald J. Wheeler's picture
Donald J. Wheeler
In Part One and Part Two of this series we discovered some caveats of data snooping. In Part Three we discovered how listening to the voice of the process differs from the model-based approach...
Donald J. Wheeler's picture
Donald J. Wheeler
Parts One and Two of this series illustrated four problems with using a model-building approach when data snooping. This column will present an alternative approach for data snooping that is of...
Donald J. Wheeler's picture
Donald J. Wheeler
In “Data Snooping Part 1” (Quality Digest, Aug. 6, 2018) we discovered the basis for the first caveat of data snooping. Here we discover three additional caveats of data snooping. Last month we...
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Donald J. Wheeler
Data mining is the foundation for the current fad of “big data.” Today’s software makes it possible to look for all kinds of relationships among the variables contained in a database. But owning a...