All Features
Donald J. Wheeler
The oldest myth about process behavior charts is the myth that they require “normally distributed data.” If you have ever heard this idea, or if you have ever taught this to others, then you need to read this article.
While this myth dates back to 1935, and while Walter Shewhart exposed this idea…
Steve Moore
Pickleball is arguably the fastest-growing sport in the United States, especially among baby-boomer retirees. This game is similar to tennis, but is played on a smaller court (44 ft × 20 ft) with a solid paddle and a perforated polymer ball much like a wiffle ball.
Pickleball’s popularity may be…
Davis Balestracci
As statistical methods become more embedded in everyday organizational quality improvement efforts, I find that a key concept is often woefully misunderstood, if it is even taught at all. W. Edwards Deming distinguished between two types of statistical study, which he called “enumerative” and “…
Jody Muelaner
In a general sense, capability is the ability to do something. Within manufacturing, capability is given a much more specific definition. It is an expression of the accuracy of a process or equipment, in proportion to the required accuracy.
This can be applied to production processes, in which…
Donald J. Wheeler
Recently I have had several questions about which bias correction factors to use when working with industrial data. Some books use one formula, other books use another, and the software may use a third formula. Which one is right? This article will help you find an answer.
Before we can…
Rohit Mathur
Whatever the process or type of data collected, all data display variation. This is also true in software development. Any measure or parameter of interest to our business will vary from time period to time period, e.g., number of incidents per week or month, time taken in resolving incidents,…
Donald J. Wheeler
During the past three months James Beagle and I presented columns that made extensive use of analysis of means techniques. Since these techniques may be new to some, this column explains when to use each technique and where to find tables of the appropriate scaling factors.
In 1967, Ellis R. Ott…
Romesh Saigal, Abdullah AlShelahi
Soon after the Great Recession, the U.S. stock markets plunged—and rebounded within 36 minutes. The Dow Jones Industrial Average dropped more than 9 percent, losing more than 1,000 points before suddenly recovering.
This May 6, 2010, event was the first recorded “flash crash.” Although it didn’t…
Scott A. Hindle
In everyday language, “in control” and “under control” are synonymous with “in specification.” Requirements have been met. Things are OK. No trouble.
“Out of control,” on the other hand, is synonymous with “out of specification.” Requirements have not been met. Things are not OK. Trouble.
Using…
Chad Kymal, Gregory F. Gruska
During the early 1980s, GM, Ford, and Chrysler established the Automotive Industry Action Group (AIAG), a not-for-profit organization with the mission “To improve its members’ competitiveness through a cooperative effort of North American vehicle manufacturers and their suppliers.” In the late…
Davis Balestracci
Recently, I’ve had a sad, increasing sense of déjà vu. Twitter has become even more vacuous, and LinkedIn has quickly devolved into a business version of Facebook. Literally right after I finished this draft, I read a newspaper headline: “Twitter Use Eroding Intelligence. Now there’s data to prove…
James Beagle III, Donald J. Wheeler
In Parts One and Two we defined the equivalence of instruments in terms of bias and measurement error based on studies using a single standard. Here we look at comparing instruments for differences in bias or differences in measurement error while using multiple standards.
When we use multiple…
Jay Arthur—The KnowWare Man
When I first learned quality improvement back in 1989 at Florida Power and Light, the consultants who trained us taught a very specific way to draw a Pareto chart. They’d been trained in Japan, the place where quality improvement first took root during the 1950s, so I took it for granted that the…
Ryan E. Day
Current business conversation often focuses on data and big data. Data are the raw information from which statistics are created and provide an interpretation and summary of data. Statistics make it possible to analyze real-world business problems and measure key performance indicators that enable…
William A. Levinson
Anthony Chirico1 describes how narrow-limit gauging (NLG, aka compressed limit plans) can reduce enormously the required sample size, and therefore the inspection cost, of a traditional attribute sampling plan. The procedure consists of moving acceptance limits t standard deviations inside the…
Adam Pintar
Now, if you’re familiar with either statistics or J.R.R. Tolkien, I know the title grabbed your attention. And if not, don’t worry; all will become clear in time, but I’ve always wanted to reference The Lord of the Rings in a title (and scientific papers provide little opportunity for that).…
Donald J. Wheeler, James Beagle III
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 more systems.
Once again we must emphasize that it makes no sense to seek to compare measurement…
Edwin Amenta
Ever since sportswriter Henry Chadwick popularized the box score in the 19th century, baseball fans have had a love affair with statistics. Many can recite records like Joe DiMaggio’s 56-game hitting streak, Rickey Henderson’s 130 stolen bases, or Barry Bonds’ 73 home runs in one season. But have…
Donald J. Wheeler, James Beagle III
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 instruments are equivalent in practice.
Churchill Eisenhart, Ph.D., while working at the U.S. Bureau of…
Davis Balestracci
In most healthcare settings, workers attend weekly, monthly, or quarterly meetings where performances are reported, analyzed, and compared to goals in an effort to identify trends. Reports often consist of month-to-month comparisons with “thumbs up” and “thumbs down” icons in the margins, as well…
Teofilo Cortizo
Within maintenance management, the term MTBF (mean time between failures) is the most important key performance indicator after physical availability.
Unlike MTTF (mean time to failure), which relates directly to available equipment time, MTBF also adds up the time spent inside a repair. That is,…
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 having a good capability or performance index. But a good index by itself does not tell the whole…
Davis Balestracci
During recent visits to Twitter and LinkedIn, I’ve become increasingly shocked by the devolution of the posts to vacuous nonsense. I felt a Network moment of, “I’m mad as hell, and I’m not going to take this anymore!”
Is your organization getting to the point where executive reaction to what’s…
Scott A. Hindle
‘Process Capability: What It Is and How It Helps,” parts one, two, three, and four, discussed Alan’s development in the field of process capability1 He’d learned about the mistakes that can be made and how to avoid them in practice to become better at his job. Alan had since passed on his learning…
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 your list of numbers into a fancy graph. What could possibly go wrong?
In the Dec. 22, 2018, issue of…
