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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)

#11

Post by eplanit »

larrydag wrote: post #5
neverartful wrote: post #2

My first job out of college (undergraduate) was working for a small consulting firm that did a lot of work in this area for the petrochemical industry and their suppliers. The owner had a PhD in decision sciences (statistics) and he did consulting work on statistical process control (SPC). This was my first exposure to this field and was so fascinated by it that after working there for a year, I quit my job so that I…

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.

Gawd, Six Sigma was an ever-present factor in all our work when I was at IBM in the late 80's to early 90's. I have complete respect for Deming, but when anything becomes "religion" it gets damaged or mis-used a lot, as you say.

In our software group, we were constantly battling with management that wanted to start to look at software development as a factory-like process, and to apply factory QA processes.

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

#12

Post by mch82 »

xyzzy21 wrote: post #9

The products I design/sell generate the inputs for this kind of thing for the semiconductor industry. It always makes cocktail party conversation complicated.

Out of curiosity, do you mean that your products generates template forms for collecting statistical sample data (like Minitab), or that your products collect measurements that are fed into tools like Minitab as data?

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

#13

Post by mch82 »

neverartful wrote: post #2

My first job out of college (undergraduate) was working for a small consulting firm that did a lot of work in this area for the petrochemical industry and their suppliers. The owner had a PhD in decision sciences (statistics) and he did consulting work on statistical process control (SPC). This was my first exposure to this field and was so fascinated by it that after working there for a year, I quit my job so that I…

Until recently, there hasn’t been enough data to apply statistical process control in a lot of fields. Chemical process companies (like Kodak used to be) have used SPC. “Web scale” companies commonly talk about running experiments now. Lots of people talk about A/B testing, which is an extremely simplistic example of SPC. I’ve been anticipating more advanced SPC tools to replace A/B testing for years, but am not aware of any. Maybe I should have created one.

Now I wonder if Machine Learning might pass up SPC as the primary method by which people identify and control key process variables.

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

#14

Post by mch82 »

larrydag wrote: post #5
neverartful wrote: post #2

My first job out of college (undergraduate) was working for a small consulting firm that did a lot of work in this area for the petrochemical industry and their suppliers. The owner had a PhD in decision sciences (statistics) and he did consulting work on statistical process control (SPC). This was my first exposure to this field and was so fascinated by it that after working there for a year, I quit my job so that I…

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.

Six Sigma is to the field of Statistical Process Control what PowerPoint templates are to the field of graphic design. The biggest problem with Six Sigma is many of the people who roll it out understand how to follow the instructions in a Six Sigma book, but don’t understand the underlying statistics well enough to recognize when the templates will fail or need to be changed.

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

#16

Post by s-luv-j »

>"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 analyzed after they get into the hands of consumers.

If your quality apparatus is purely inspection based, you will live your life one escalation to the next.

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

#17

Post by onion2k »

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.

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

#18

Post by s-luv-j »

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.

One of the reasons why pushing change straight to production with A/B testing works so well is that you can expose your new change to statistically significant real user load and, assuming your have decent instrumentation, find the problems. This does mean that a subset of your users get exposed to those problems.

A more user friendly way would be to have a scaled down replica of production setup with simulators that mimic user behavior. Assuming the development team actually believes in and tends this environment, they will find the lion's share of bugs that commonly slip through peer review.

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

#19

Post by neverartful »

cafard wrote: post #3
neverartful wrote: post #2

My first job out of college (undergraduate) was working for a small consulting firm that did a lot of work in this area for the petrochemical industry and their suppliers. The owner had a PhD in decision sciences (statistics) and he did consulting work on statistical process control (SPC). This was my first exposure to this field and was so fascinated by it that after working there for a year, I quit my job so that I…

Twenty-five or thirty years ago, one hear a great deal about total quality management (TQM).

Yep, it was back in the early 1990s.

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

#20

Post by neverartful »

mch82 wrote: post #13
neverartful wrote: post #2

My first job out of college (undergraduate) was working for a small consulting firm that did a lot of work in this area for the petrochemical industry and their suppliers. The owner had a PhD in decision sciences (statistics) and he did consulting work on statistical process control (SPC). This was my first exposure to this field and was so fascinated by it that after working there for a year, I quit my job so that I…

Until recently, there hasn’t been enough data to apply statistical process control in a lot of fields. Chemical process companies (like Kodak used to be) have used SPC. “Web scale” companies commonly talk about running experiments now. Lots of people talk about A/B testing, which is an extremely simplistic example of SPC. I’ve been anticipating more advanced SPC tools to replace A/B testing for years, but am not awar…

Actually, it does not take a huge amount of data to make use of statistical process control. In fact, it's so little that someone should be able to do it with paper, pencil, and calculator.

The statistical technique I think that's better able to displace A/B testing is design of experiments (DOE). This approach also does not require that much data to implement. There was an excellent youtube series on it where the presenter used popping popcorn for his experiments. I can't seem to find it now.

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