Content by Donald J. Wheeler
Problems With Gauge R&R StudiesHow to make sense of your repeatability and reproducibility (R&R) values
Mon, 01/03/2011 - 04:30
Measurement error is ubiquitous. As a result, over the past 250 years, different areas of science and engineering have come up with many different ways to deal with the problem. One approach to the problem of measurement error was developed during… The Intraclass Correlation CoefficientIs your measurement system adequate?
Thu, 12/02/2010 - 15:26
In my July column, “Where Do Manufacturing Specifications Come From?” we found that the intraclass correlation coefficient is the natural measure of relative utility. This measure is theoretically sound and easy to explain. This column will look at… Are You Sure We Don’t Need Normally Distributed Data?More about the misuses of probability theory
Mon, 11/01/2010 - 06:00
Last year I discussed the problems of transforming data prior to analysis (see my August 2009 column, “Do You Have Leptokurtophobia?,” my September 2009 column, “Transforming the Data Can Be Fatal to Your Analysis,” and my October 2009 column,“… What Is the Zone of Economic Production?And how can you get there?
Mon, 10/04/2010 - 05:30
In my August column, “How to Turn Capability Indexes Into Dollars,” and my September column, “The Gaps Between Performance and Potential,” I showed how to convert capability indexes into the effective cost of production and use (ECP&U), and how… The Gaps Between Performance and PotentialUsing the effective costs of production and use
Wed, 09/01/2010 - 06:00
In my August column, “How to Turn Capability Indexes Into Dollars,” I defined the effective cost of production and use and showed how it can be obtained directly from the capability and performance indexes. In this column, I will show how these… How to Turn Capability Indexes Into DollarsThe effective cost of production and use
Fri, 07/30/2010 - 08:03
Capability indexes allow us to characterize the relationship between the process potential and the specifications. Performance indexes characterize the past performance relative to the specifications. Yet, in practice, we seek to make sense of… Where Do Manufacturing Specifications Come From?Standard deviation of conditional distribution of X given Y is the reason all measurement studies are built upon repeated measurements.
Tue, 07/06/2010 - 08:40
Evidently Steven Ouellette did not like my June column, “Is the Part in Spec?” The adjectives he used were “complicated,” “unhelpful,” “backward,” “confusing,” “unnecessary,” “crazy,” and “disastrous.” (Ouellette’s response, “Know the Process… Is the Part in Spec?Since data is always imperfect, how can we ever know if a measured item is within the specifications?
Tue, 06/01/2010 - 10:02
During the past 20 years it has become fashionable to condemn measurement processes that are less than perfect. Yet the reality is that we must always use imperfect data. Given this fact of life, how can we ever know if a measured item is or is not… Two Routes to Process Improvement--Part 2Assignable causes and common causes
Thu, 05/06/2010 - 07:00
Having an effective model for the nature of data will inevitably identify two different paths to process improvement. One path seeks to operate a process up to its full potential while the other path seeks to operate to meet requirements. This… Two Routes to Process Improvement--Part 1Cause-and-effect relationships
Wed, 05/05/2010 - 07:00
Having an effective model for the nature of data will inevitably identify two different paths to process improvement. One path seeks to operate a process up to its full potential while the other path seeks to operate to meet requirements. This…
