All Features
Bruce Hamilton
For many years I worked for a manufacturer of pressure and temperature switches, a small company with a very big product selection. In our product catalog there were roughly three dozen distinct product families with hundreds of standard products, each available with thousands of optional…
Joel Smith
A couple of years ago, I wrote a blog post titled "What I Learned From Treating Childbirth as Failure" that conveniently ended up getting published the day before my daughter was born. You should read it first, but to summarize, it demonstrates how we can predict the odds of an event happening…
Dan Nelson
When we think of plan-do-check-act (PDCA), W. Edwards Deming might spring to mind… and Walter Shewhart, maybe Kaoru Ishikawa as well. But the thinking that results from PDCA today can most always be traced to Shewhart’s 1939 book, Statistical Method From the Viewpoint of Quality Control; these…
Kevin Meyer
I’ll preface this article by saying that yes, I’m from crazy California. I eat granola with fruits and nuts in the morning, am vegetarian (well, pescatarian), dislike wearing shoes, and practice yoga. At least I don’t have dreadlocks—yet. So there—now you’re warned.
I’m currently winging my way…
Mike Micklewright
Years ago, there was a memorable TV commercial of a toaster waffle that had this very memorable tag line: “Leggo my Eggo.” Today, this product still exists, as does the tag line, but the tag line is much more obscure than it once was.
Today, CEOs and top executives everywhere are quaking in their…
Bruce Hamilton
An old TV series I watched recently reminded me of an experience I’ve had many times in my work. In this I Love Lucy episode, Lucy is ordered by Ricky to create a schedule to make her “more efficient.” A schedule board, posted in their home, is a “best practice,” but without the best intent. The…
Alan Nicol
When we learn the ways of lean methodology, we’re taught that there are two types of waste: pure waste, which needs to be eliminated; and necessary waste, which does nothing to improve our performance or profits but must be produced anyway.
I’ve decided that there’s a third type of waste, called…
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)…