Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Statistical process control after W. Edwards Deming

2uo.de

Post reply on HN
Print view View original

21–30 of 35 posts

Re: Statistical process control after W. Edwards Deming

#21

Post by steppi »

kqr wrote: post #15
deterministic wrote: post #12

If you are interested in this you might also like the book “The Goal”. It is a business novel introductions TOC (the Theory of Constraints) which IMHO is the #1 most efficient way to run a company/team/process/…

The problem with the theory of constraints is that it, from my understanding, uses inner constraints to determine boundary ingress rates. This causes higher variation than necessary. When a bottleneck is introduced, you will have a lot of crap backed up in front of it because you ran upstream processes at high rates into the bottleneck – even though you knew the bottleneck was there. When the bottleneck is lifted, yo…

This problem actually comes up in The Goal. After the characters lift the bottlenecks in their factory, things go smoothly for a while but then they start to see starvation in other areas like you mentioned. The solution they come up with involves local signaling and also data collection and analysis to understand the timeframes in play within the factory. The following excerpt is from Chapter 26.

Then I said, "Fine, but how do we time each release of material so it arrives at the bottleneck when it's needed?" Stacey said, "I'm not sure, but I see what you're worried about. We don't want the opposite problem of no work in front of the bottleneck." "Hell, we got at least a month before that happens, even if we released no more red tags from today on," said Bob. "But I know what you mean. If we idle the bottleneck, we lose throughput." "What we need," I said, "is some kind of signal to link the bottlenecks with the release-of-materials schedule." Then Ralph, to my surprise, spoke up and said "Excuse me, this is just a thought. But maybe we can predict when to release material by some kind of system based on the data we've kept on both the bottlenecks."

Re: Statistical process control after W. Edwards Deming

#22

Post by jimmygrapes »

dsr3 wrote: post #16

If I am interested in learning Deming ideas and theory, what is the textbook/book that I should read? Any recommendation?

The Essential Deming[1] is probably the gold standard for now, though it can be a little dry. It's one of those "suggested readings" in basically any safety or process management higher education curricula.

Not really 100% about Deming but very relevant, I would recommend Alfie Kohn's "Punished by Rewards" [2] as a supplement to understand some of the implications of what happens when Deming's ideas are implemented without understanding the human condition.

Otherwise, Deming wrote and published plenty of his own work that is worth reading.

[1]: https://www.amazon.com/Essential-Deming-Leadership-Principle...

[2]: https://www.amazon.com/Punished-Rewards-Trouble-Incentive-Pr...

Re: Statistical process control after W. Edwards Deming

#23

Post by haltingproblem »

cardosof wrote: post #4

I've used Deming's ideas to optimize ads and it did work way better than bayesian ab testing or ML-based approaches. However, management did not like that I was using something so old, so I had to rebrand it, but it was Deming still.

Any chance of you doing a writeup on using Deming's idea to optimize ads? That would be a very interesting read as most ad optimization methods lack in intellectual rigor and controls.

Re: Statistical process control after W. Edwards Deming

#25

Post by dsr3 »

wsh wrote: post #20
dsr3 wrote: post #16

If I am interested in learning Deming ideas and theory, what is the textbook/book that I should read? Any recommendation?

For Deming’s own ideas, such as the 14 Points, see his book Out of the Crisis (1986), reprinted by MIT Press. For the practical application of control charts and other techniques (due originally to Shewhart and others), see the Statistical Quality Control Handbook (Western Electric, 1958) or, for a more up-to-date treatment, the NIST/SEMATCH e-Handbook of Statistical Methods : https://www.itl.nist.gov/div898/handbook…

Thank you, I am more interested about the latter (implementation of his techniques at industrial setting). Will check that soon.

Re: Statistical process control after W. Edwards Deming

#26

Post by throwaway892238 »

I'm so happy when people bring up the "...wtf" side of Deming, in context of his more useful contributions. Hero worship is bullshit. A person who has really great ideas also has really crap ideas, because nobody is perfect. We should be more comfortable humanizing people, so we don't get trapped in the cargo cult or appeal to authority, and so we can accept more ideas from people who don't look like geniuses.

All that said: I find it so fascinating that his focus was on statistics and science, when so much of his advice is actually holistic observations from experience, and not all the result of scientific experiments or research. There is both a science and an art to making an organization (read: a group of people doing organized work) work well. You really need both, because people are, unfortunately, not science experiments, but weird blobs of meat and emotions interacting in an unfathomably complex system of systems of systems.

Re: Statistical process control after W. Edwards Deming

#27

Post by kqr »

steppi wrote: post #21
kqr wrote: post #15

Earlier quoted context omitted.

The problem with the theory of constraints is that it, from my understanding, uses inner constraints to determine boundary ingress rates. This causes higher variation than necessary. When a bottleneck is introduced, you will have a lot of crap backed up in front of it because you ran upstream processes at high rates into the bottleneck – even though you knew the bottleneck was there. When the bottleneck is lifted, yo…

This problem actually comes up in The Goal . After the characters lift the bottlenecks in their factory, things go smoothly for a while but then they start to see starvation in other areas like you mentioned. The solution they come up with involves local signaling and also data collection and analysis to understand the timeframes in play within the factory. The following excerpt is from Chapter 26. Then I said, "Fine…

Yes, but also no. Prediction implies somewhat steady flow. That is of course the ideal! If you know roughly how much is going to be needed when you can just run things to schedule and you don't need any signals at all!

The problematic case is when variation is too big for that. That's when (from my memory -- was a while since I read the books) Goldratt leans on global ingress control instead of local signaling.

But I do realise I may be misremembering. I should probably re-read some time soon.

Re: Statistical process control after W. Edwards Deming

#28

Post by tgv »

That's probably the first text on business/management that I found interesting to read. In my (limited) experience, such texts are usually extremely dry, and lack any logic. Often they seem to recommend abstract rules without any reason. This text was more "reasonable", and the funnel experiment is very suggestive.

BTW, why woiuld the author wonder about the multiplication of loss and probability? Why would it be a convolution? I suppose the intention is to minimize expected loss.

Re: Statistical process control after W. Edwards Deming

#29

Post by tome »

kqr wrote: post #27
steppi wrote: post #21

Earlier quoted context omitted.

This problem actually comes up in The Goal . After the characters lift the bottlenecks in their factory, things go smoothly for a while but then they start to see starvation in other areas like you mentioned. The solution they come up with involves local signaling and also data collection and analysis to understand the timeframes in play within the factory. The following excerpt is from Chapter 26. Then I said, "Fine…

Yes, but also no. Prediction implies somewhat steady flow. That is of course the ideal! If you know roughly how much is going to be needed when you can just run things to schedule and you don't need any signals at all! The problematic case is when variation is too big for that. That's when (from my memory -- was a while since I read the books) Goldratt leans on global ingress control instead of local signaling. But I…

I read it more recently than you and your memory matches mine. I was always surprised The Goal taught a push-based method rather than a pull-based one.

Re: Statistical process control after W. Edwards Deming

#30

Post by deterministic »

tome wrote: post #29
kqr wrote: post #27

Earlier quoted context omitted.

Yes, but also no. Prediction implies somewhat steady flow. That is of course the ideal! If you know roughly how much is going to be needed when you can just run things to schedule and you don't need any signals at all! The problematic case is when variation is too big for that. That's when (from my memory -- was a while since I read the books) Goldratt leans on global ingress control instead of local signaling. But I…

I read it more recently than you and your memory matches mine. I was always surprised The Goal taught a push-based method rather than a pull-based one.

What I learned from "The Goal" is that any business/system will always have a single bottleneck that dictates the max throughput of the whole business/system.

So as a manager it is your #1 objective to find that bottleneck and remove it. And the moment you remove it, the max throughput of the whole business/system improves until some other bottleneck is now limiting throughput. So you repeat finding and fixing that bottleneck etc.

There are of course different ways to fix the bottleneck. Kanban is a famous example of one. However even with Kanban the business will still have a bottleneck that limits throughput.

Post reply on HN