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Statistical process control after W. Edwards Deming (2020)

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Re: Statistical process control after W. Edwards Deming (2020)

#41

Post by avs733 »

marcosdumay wrote: post #33
winslett wrote: post #30

I stumbled upon Deming's "Out of the Crisis" when wandering through the library in school. It has changed how I thought about system improvement ever since. I use the things I learned for marketing, product, and engineering systems. Want to improve a system? Before doing anything, collect data and measure. A system must be stable, else you cannot improve it. Marketing campaigns. Funnel optimizations. Performance impr…

Well, keep in mind that "improvement" here implies non-transformative change (we usually call this "optimization" on informatics). If you are not sure you have the correct system running, stabilizing it is the last thing you want.

I think that may be a too narrow vision of “transformative” improvement.

I worked in a factory where one of the biggest, and hardest, improvements we made was coaching the managers and engineers to leave the technicians alone when they were doing maintenance.

We collected data on how often they were interrupted, how much time it cost, and how interruptions could lead to RIT changes in procedures that affected quality.

Previously the engineers and managers saw the checking as helping because they could se ethe status of things and observe and answer questions, many would even lend a hand. Oversight and engagement was seem as a path to improved quality. To let go of that was a huge transformation. It started with data - a lot of data - that allowed us to identify that weekend and night maintenance generally went faster and better.

Re: Statistical process control after W. Edwards Deming (2020)

#42

Post by hef19898 »

wheelinsupial wrote: post #38
larrydag wrote: post #5

Earlier quoted context omitted.

GE and other companies tried to implement Demings approach. They called it Six Sigma. Those that used Deming's concepts were successful. Yet too many misunderstood the idea of SPC and used in areas that was not meant for quality control. For instance trying to use SPC in the managerial process itself.

I’m reading a book called Working Backwards about Amazon. There is a chapter on metrics and it says to use the DMAIC process, which comes from six sigma, for developing reporting and metrics. The authors provide an example about applying this to e-commerce at Amazon. They don’t seem to use control charts, but they are still trying to examine the metrics for common vs special cause of variation. If you can relate inpu…

Amazon, the Supply Chain part of it at least, has one of the best metrics systems I have ever seen in my life. Every metric is measuring something meaningful, each one is measuring a crucial process interface, each one is based on a simple calculation. Also most are measured in DPMO, looking at defects instead of things meeting expectations. The funny thing is, during my time metrics where presented, across all levels, in blunt, no chart, tables in a auto created PDF. And yet this is still light years ahead of everything else I saw, including fancy control towers.

Re: Statistical process control after W. Edwards Deming (2020)

#43

Post by afarrell »

onion2k wrote: post #17
s-luv-j wrote: post #16

>"You can not inspect quality into a product." ~Deming Yep. This applies double to software. Putting software under load and trending health measures to look for two standard deviations variance is very similar to how Deming instrumented production lines. The neat thing that software enables for both automobile manufacturing and software products themselves is that those exact same health measures can be trended and…

I've spent much of the past few years trying to work out if this means I should stop relying on pull requests to catch problems, and put something in place ahead of writing code instead, but so far I've not figured out an alternative that works. If anyone has any ideas, please share them.

Pair-drafting pseudocode with a colleague into a Dropbox Paper document is a great way to evaluate tradeoffs.

Re: Statistical process control after W. Edwards Deming (2020)

#44

Post by marcosdumay »

avs733 wrote: post #41
marcosdumay wrote: post #33

Earlier quoted context omitted.

Well, keep in mind that "improvement" here implies non-transformative change (we usually call this "optimization" on informatics). If you are not sure you have the correct system running, stabilizing it is the last thing you want.

I think that may be a too narrow vision of “transformative” improvement. I worked in a factory where one of the biggest, and hardest, improvements we made was coaching the managers and engineers to leave the technicians alone when they were doing maintenance. We collected data on how often they were interrupted, how much time it cost, and how interruptions could lead to RIT changes in procedures that affected quality…

Well, I claim that is a way too broad definition of "transformative". The people kept creating the same products, by almost the same procedure.

Re: Statistical process control after W. Edwards Deming (2020)

#45

Post by zepto »

marcosdumay wrote: post #33
winslett wrote: post #30

I stumbled upon Deming's "Out of the Crisis" when wandering through the library in school. It has changed how I thought about system improvement ever since. I use the things I learned for marketing, product, and engineering systems. Want to improve a system? Before doing anything, collect data and measure. A system must be stable, else you cannot improve it. Marketing campaigns. Funnel optimizations. Performance impr…

Well, keep in mind that "improvement" here implies non-transformative change (we usually call this "optimization" on informatics). If you are not sure you have the correct system running, stabilizing it is the last thing you want.

> If you are not sure you have the correct system running, stabilizing it is the last thing you want.

Stable in this case just means you are clear what the system is and can keep operating it if you want to.

That is a prerequisite to evaluating the system in order to determine whether it is what you want.

Re: Statistical process control after W. Edwards Deming (2020)

#46

Post by WWWWH »

WWWWH wrote: post #15

This is a great article, but is there a good modern source (say an introductory text book) on these ideas? I've a vague memory of doing this as a first year undergraduate, but that was a long time ago. And stupidly, I didn't think I'd ever need them...

Thanks for the tips guys. I’ll check them out. I also pulled a copy of Box’s essays off the shelf, and while he is obviously mainly interested in experimental design he does drop in a few references to oldish books on SPC.

Re: Statistical process control after W. Edwards Deming (2020)

#47

Post by Zigurd »

Jtsummers wrote: post #34
hikarudo wrote: post #32

Earlier quoted context omitted.

> Software is completely different, it is hardly ever a repeatable process to create software. Making the same software over and over is nonsensical, but making a billion identical contact lenses is exactly what you want. I've heard it said like this: Creating a software is like developing a recipe for a cake. Baking thousands of cakes (a "manufacturing process") is what you do once you have the recipe. The two activ…

Kind of. We have to clarify what we mean by "creating a software". This seems to be rarely done in most discussions on processes for software development. The lack of information regarding this means that everyone gets to be right and angry at everyone else. Are you making novel systems? Then it's like developing a recipe for a cake. Are you making bog standard CRUD web apps? Then you're baking thousands of cakes. A…

Certainly some software looks routine and feels repetitious while you are doing it. But very little if any software is amenable to determining its manufacturing tolerances. That phrase is jarring because the idea of manufacturing tolerances for software does not make sense. But manufacturing tolerances are fundamental to statistical process control, which then builds on statistically valid sampling to determine if part of a process is failing. (Or it can determine that a quality issue is something other than a process failure.) But it depends on setting and using manufacturing tolerances wisely.

Re: Statistical process control after W. Edwards Deming (2020)

#48

Post by rramadass »

User23 wrote: post #28

Deming gets the credit, but in Japan it was Homer Sarasohn[1][2] who did the foundational work[3]. In fact, he handed the reins off to Deming. One particularly interesting thing is that, at least once upon a time, Canon didn't even bother inspecting their copiers and printers, because the variance was so low it was a waste of time[4]. [1] https://en.wikipedia.org/wiki/Homer_Sarasohn [2] https://honoringhomer.net/ [3]…

This is great; had never known about Homer Sarasohn before. So many amazing people have been lost to the vagaries of history that it behooves us to research and rediscover our "lost" heroes.

Thanks for all the links; can you recommend some introductory books on the subject?

Re: Statistical process control after W. Edwards Deming (2020)

#49

Post by User23 »

rramadass wrote: post #48
User23 wrote: post #28

Deming gets the credit, but in Japan it was Homer Sarasohn[1][2] who did the foundational work[3]. In fact, he handed the reins off to Deming. One particularly interesting thing is that, at least once upon a time, Canon didn't even bother inspecting their copiers and printers, because the variance was so low it was a waste of time[4]. [1] https://en.wikipedia.org/wiki/Homer_Sarasohn [2] https://honoringhomer.net/ [3]…

This is great; had never known about Homer Sarasohn before. So many amazing people have been lost to the vagaries of history that it behooves us to research and rediscover our "lost" heroes. Thanks for all the links; can you recommend some introductory books on the subject?

On the subject of "lost" heroes? Not really, I've just come across a few in the course of my life. It would certainly make a great book though!

Re: Statistical process control after W. Edwards Deming (2020)

#50

Post by rramadass »

User23 wrote: post #49
rramadass wrote: post #48

Earlier quoted context omitted.

This is great; had never known about Homer Sarasohn before. So many amazing people have been lost to the vagaries of history that it behooves us to research and rediscover our "lost" heroes. Thanks for all the links; can you recommend some introductory books on the subject?

On the subject of "lost" heroes? Not really, I've just come across a few in the course of my life. It would certainly make a great book though!

I was asking about books on Statistical Process/Quality Control though a book on our "lost heroes" would make a more enjoyable reading :-)

It seems Japan's resurgence after WWII owes a lot to the enlightened policies of a "few" Americans and their willingness to actually follow through with concrete actions. I wonder how many Japanese really know about their own history and what they really owe the US.

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