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Patrick Runkel
My previous article examined how an equivalence test can shift the burden of proof when you perform a hypothesis test of the means. This allows you to more rigorously test whether the process mean is equivalent to a target or to another mean.
Here’s another key difference: To perform the analysis…
Ryan E. Day
And so the debate rages on about whether the wildly popular Flappy Bird app is actually a tool for teaching lean or teaching theory of constraints. Really? No, not really. But at least I’m not the only one thinking about it.
Actually, it was Jens Woinowski’s article “What You Can Learn about Lean…
Patrick Runkel
With more options come more decisions. With equivalence testing added to Minitab 17, you now have more statistical tools to test a sample mean against target value or another sample mean.
Equivalence testing is extensively used in the biomedical field. Pharmaceutical manufacturers often need to…
Dan Nelson
Why is internal auditing important to your quality management system (QMS)? To ensure that processes conform to ISO 9001 requirements, or to ensure that the company conforms to management’s own defined plans? Although audits can be done for both reasons, the second choice is more important.…
Davis Balestracci
To summarize my last three articles, most improvement approaches come out of the same theory and are based on the assumption that everything is a process.
The universal process flowchart in Figure 1 sums it up beautifully. The boxes at the top are how executives think the process works. The…
Lean Math With Mark Hamel
Available time for changeovers per period (Ta∆), also called available time for (internal) setups, represents the time per a given period (e.g., day, shift, week) during which a machine, equipment, or resource can be changed over (i.e., from one product to another, prepared for a different medical…
Carly Barry
Ugh, your process is producing some parts that don’t meet your customer’s specifications. Fortunately, after a little hard work, you find a way to improve the process.
However, you want to perform the appropriate statistical analysis to back up your findings and make it easier to explain the…
David Muil
Management systems are sometimes misunderstood as nothing more than a heavy administrative burden providing limited business benefit. In fact, many organizations with management systems in place haven’t effectively defined the processes they actually employ at all. Perhaps it’s because they think…
Donald J. Wheeler
Why bother to plot your data? A simple shortcut is available that will allow you to do your analysis without the data getting in the way. How do you accomplish this breakthrough? Read on.
This marvelous advance in analysis is known as the “data-free graph.” As usual we begin with a collection of…
Mike Micklewright
Editor’s note: This article discusses topics covered at greater length in episodes 19–23 of a new streaming video training series, Creating and Sustaining Lean Improvements—Integrating Principles, Culture, and Tools by the author and 360 Performance Circle, a sister company to Quality Digest.…
Matthew J. Savage
Lori, a software customer, phoned to ask if Cpk is the best statistic to use in a process that slits metal to exacting widths. As a PQ Systems technical support analyst, I too wondered what index would be best suited for her application, a highly specialized one. Perhaps Cpk, Ppk, Cpm, or some…
Bruno Scibilia
My main objective is to encourage greater use of statistical techniques in the service sector and present new ways to implement them.
In a previous blog, I presented an approach you can use to identify process steps that may be improved in the service sector (quartile analysis). here I’ll show…
Matthew Barsalou
While reading a list of 5S activities, I thought, “Am I mistaken?” The activities on the list didn’t match what I thought they should be. I dug a little deeper and discovered there has been a lot of variation in the translation from Japanese to English for the methodology called 5S, which is often…
Lean Math With Mark Hamel
Triangle kanban, one of three types of signal kanban, is unique in that there is only a single kanban per part number or stock-keeping unit. Accordingly, kanban-sizing math has nothing to do with determining the number of kanban; that’s obviously fixed.
Instead, the math is focused on determining…
Davis Balestracci
My last column, “Can We Please Stop the Guru Wars?” made the case that the various improvement approaches are all pretty much the same. To recap, there are seven sources of problems with a process. The first three sources help frame the situation.
They are: Source No. 1. Inadequate knowledge of…
Bruce Hamilton
Across a large swath of the United States, the winter has been especially cold, snowy, and dreary this year. So here’s a post with a link to a cheery video at the end, just to pick my spirits up—and maybe yours, too.
The English language can be confounding. For example, the word “turkey” is slang…
Jim Benson
How do you know when to clean up your kanban’s Done column? When it’s full.
When we showed our board to people in classes and on consulting engagements, the Done column showed that we were really, really productive. It was huge. It went on forever. Hundreds of completed tasks.
So, how do we clean…
Donald J. Wheeler
Students typically encounter many obstacles while learning statistics. In 44 years of teaching I have discovered some distinctions that help students overcome these obstacles. This article will remove some sources of confusion concerning the relationship between statistical process control (SPC)…
David Schwinn
I was reminded recently of the passing of Thomas Berry, one of the most eminent cultural historians of our time. His work and insight have been touchstones for me for the last 30 years.
For me, the story starts in 1993 when my wife, Carole, and I were invited to help the folks in the North Simcoe…
Jay Arthur—The KnowWare Man
Let’s face it: Everyone isn’t cut out to be a belted Six Sigma guru, but everyone should know how to use key tools in the right order to solve the problems facing businesses. And they can’t wait months or years to get results; the marketplace moves too quickly.
During the early 1990s, I attended…
Mark R. Hamel
Larry Loucka, a close friend and colleague, recently pointed me to a Feb. 16, 2014, article in The Wall Street Journal (WSJ). Now, before you roll your eyes and give me the WSJ-isn’t known-for-getting-the-lean-thing-right look, hear me out. What the journal published is really, really good stuff—…
Bob Emiliani
Let’s get rid of value stream maps. I can hear it now: “Why would you say such a thing? Value stream maps are great. We can’t see waste without them.”
Precisely.
Value stream maps have developed an outsized importance in relation to other types of basic information that one gathers when trying to…
Mike Micklewright
Editor’s note: Mike Micklewright will be a guest on Quality Digest Live, on Feb. 28, 2014, at 11 a.m. Pacific/2 p.m. Eastern. Micklewright will also present a webinar, “Sustaining Lean Improvements While Adding Spark to Your QMS,” on March 6, 2014, at 11 a.m. Pacific/2 p.m. Eastern.
Many years ago…
John Flaig
Engineers have used safety margins for centuries to protect their companies and customers from the consequences of product degradation and failure. Sometimes the safety margins are fairly obvious (e.g., maximum-load limits posted in elevators), and other times they’re not.
Design margins are…
Mark Rosenthal
Over the years, I’ve observed a number of efforts at various companies to implement A3 problem solving, an approach based on the plan-do-check-act (PDCA) cycle that summarizes the problem and solution on a folded form, usually 11 in. × 17 in. I worked for some of those companies; I’ve observed…