Content by Davis Balestracci
Why Did Total Quality Management Fail?Employees take their cues from management.
Thu, 08/06/2009 - 05:00
Do top managers still view financial performance as the sole indicator of success, despite mouthing platitudes about dazzled customers and fulfilled employees? Is there a point when reductions are done excessively in the name of squeezing out a few…
The Engine and Fuel of Quality ImprovementOrganizational change would be so easy if it weren’t for all the people.
Tue, 07/14/2009 - 14:35
“I suffer simultaneously from amnesia and déjà vu. I have the feeling that I keep forgetting the same thing over and over again.” —Steven Wright (surreal comedian) It all seems so logical, doesn’t it? Focus on processes, improve your…
The Wisdom of David Kerridge—Part 2Statistics in the real world aren't quite as tidy as those in a text book.
Thu, 07/09/2009 - 04:00
Click here to read part 1 of this series. Analytic statistical methods are in very strong contrast with what is normally taught in most statistics textbooks, which describe the problem as one of “accepting” or “rejecting” hypotheses. In the real…
The Wisdom of David Kerridge, Part 1Back to basics
Tue, 06/30/2009 - 03:00
This is an expanded version of an article that Balestracci wrote for Quality Digest in December 2007.  --Editor I discovered a wonderful unpublished paper by David and Sarah Kerridge several years ago (Click here to get a pdf). Its influence on…
Good-Bye for Now…… and Godspeed on your statistical journey
Tue, 12/02/2008 - 11:44
As this is my last column for Quality Digest, I’m delighted to announce that my distinguished predecessor, Donald J. Wheeler, will be writing this column again. You’ll be in good hands. When I got my master’s degree in statistics in 1980, jobs…
How Do You Treat Special-Cause Signals?By using your brain…
Wed, 10/29/2008 - 15:35
Take a look at the control chart in figure 1. There are no observations outside the common-cause limits, but there are five special-cause flags: • Observation 5: Two out of three consecutive points greater than two standard deviations away…
An Underrated Test for Run ChartsThe total number of runs above and below the median proves revealing.
Fri, 10/03/2008 - 14:15
Suppose you had 16 months of data on an important process (as plotted on the run chart seen in figure 1). For improvement purposes, an intervention was made after the sixth observation to lower this key process indicator. This intervention is…
Considering Golf… StatisticallyA better way to teach “the basics”?
Sat, 08/30/2008 - 14:58
This column is in honor of the first anniversary of my late father’s death. In his last days, Dad enjoyed watching golf, and I’d often join him. Watching the recent British Open, I thought I would apply some basic statistical principles to the…
Analyzing Rare Occurrences of EventsWhen to use Fisher’s Exact Test
Fri, 08/01/2008 - 08:14
Eighty-four doctors treated 2,973 patients, and an undesirable incident occurred in 13 of the treatments (11 doctors with one incident and one doctor with two incidents), a rate of 0.437 percent. A p-chart analysis of means (ANOM) for these data is…
More Statistical Stratification With Count DataThe u-chart ANOM
Tue, 02/20/2018 - 12:03
In a recent column, I discussed some key concepts of count data, especially the importance of a clear definition of the threshold where something goes from a nonevent (x = 0) to a tallied event (x = 1). In addition, all count data have an implicit…