William A. Levinson
The phrase “flatten the curve” means to slow the transmission of the coronavirus (Covid-19) in order to spread the total number of cases out over a longer period of time. This will avoid overwhelming...
Donald J. Wheeler
This article is an update to “Tracking Covid-19” that Al Pfadt, Kathryn Whyte, and I wrote last week. In that article we summarized what is known about Covid-19, what has already happened, and...
Donald J. Wheeler
Based on the professional literature available, there are some inconvenient truths about Covid-19 that are not always considered in the chorus of confusion that exists today. Here we summarize...
Donald J. Wheeler
Lean production is built on the explicit assumption that each step is operated predictably and capably. Predictable operation can only be achieved and maintained by using process behavior charts....
Peter Dizikes
Given the complexities of healthcare, do basic statistics used to rank hospitals really work well? A study co-authored by MIT economists indicates that some fundamental metrics do, in fact, provide...
Donald J. Wheeler
Short Run SPC, Part 1 and Part 2 showed how to use zed charts and difference charts to track the underlying process while making different products. This part will illustrate both the...
Davis Balestracci
Editor’s note: The following browsable offering from Davis Balestracci represents a good chunk of his knowledge base. If you’re looking for improvement ideas, motivation, or a swift kick in the pants...
Donald J. Wheeler
Lean production is built on the explicit assumption that each step is operated predictably and capably. Predictable operation can only be achieved and maintained by using process behavior charts. But...
Dirk Dusharme @ Quality Digest
What a year.
No matter your job, your industry, or your political beliefs, this year has been a heck of a ride. The (still ongoing) trade war with China, manufacturing gains (and losses), the 737 MAX...
Quality Digest
As usual with Quality Digest’s diverse audience, this year’s top stories covered a wide range of topics applicable to quality professionals. From hardware to software, from standards to risk...
Donald J. Wheeler
Lean production is built on the explicit assumption that each step is operated predictably and capably. Predictable operation can only be achieved and maintained by using process behavior charts...
Harish Jose
It has been a while since I have written about statistics, and I get asked a lot about a way to calculate sample sizes based on reliability and confidence levels. So today I am sharing a spreadsheet...
Donald J. Wheeler
In the past two months we have looked at how three-sigma limits work with skewed data. This column finds the power functions for the probability limits of phase two charts with skewed probability...
Jody Muelaner
One of the key ideas in lean manufacturing is that defects should be detected as early as possible. Efforts to control manufacturing processes, so that issues can be detected before defects...
Bill Snyder
In 1500, China’s economy was the strongest in the world. But by the 19th century, the United States, Western Europe, and Japan had leapfrogged over China by churning out goods and services in vast...
Anthony D. Burns
You’ve set aside Sunday afternoon to bake some cookies, but you discover you have run out of eggs. Your partner in marital bliss has gone out and taken the car. You call a couple of mates, and they...
Christopher Shoe
According to a recent LNS Research survey, 37 percent of quality leaders cite an inability to measure quality metrics as their No. 1 barrier to achieving quality goals. Even worse, the survey...
Donald J. Wheeler
Last month I looked at how the fixed-width limits of a process behavior chart filter out virtually all of the routine variation regardless of the shape of the histogram. In this column I will look at...
Yen Duong
If you think it’s hard to tell how you’re doing at your job, imagine being a hockey goalie. Let’s say you block every shot in a game. Was that performance due to your superior skills? Or maybe just...
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...
