After companies had done well with Six Sigma for a few years, they saw that what was holding the back in terms of quality and cost was the design of products. So DFSS was developed. It is basically a toolset and methodology for designing new products and services to maximize quality and minimize cost. It uses quite a bit of software to do things like model the product’s performance characteristics, perform statistical tolerance generation, and other cool stuff. It was the big second wave of Six Sigma related stuff.
Great question. My question is why so many people never ask! It would drive me crazy until I knew! Anyway… A sigma is referring to the statistical concept of a standard deviation. The standard deviation is usually represented by the Greek letter sigma. The standard deviation tells us now much variation is in a process. For example, if you made baseballs, and if you could weigh them accurately enough, you would see that each one weighs a little different. Hopefully they are all within the specifications set forth by MLB, or whoever.
When products are very consistent with very little variation, they don’t cause much trouble. If we made baseballs and they had a lot of variation in their weight, it would be a problem, especially for the pitcher and probably the batter too! So low variation is good. So small standard deviations are good.
Because of some statistical properties of groups of data (“distributions”), we can count how many standard deviations can fit between the average and the upper specification of lower specification. The more the better. If we can only fit 3, we have a 3 sigma process, and are going to make a lot of defects. As the sigma level gets higher, it means we are getting more consistent, and making very few defects. When we get to 6 sigma, we only have about 3 to 4 defect out of every million things we make. That’s a very high quality level. Often times it also means less scrap and rework at the factory. So, many times we can make the quality better, and save costs at the same time. Pretty cool, isn’t it?
So why not go higher than 6? At times we do, like in airline safety, nuclear reactors, etc. But for many products, to get much past 6 sigma, you have to start spending more money, so the cool thing about saving money doesn’t work so well. And most companies find 6 sigma to be a tough enough goal by itself!
Six Sigma has also become a program, a workflow, a toolset, and may have other meanings to various organizations. In general, it is a methodology to help companies do their stuff Better, Faster, Safer, Lower Cost, and less Environmental Impact. That’s why so many companies are into it.
PEM means Psychological and Emotional Methods, referring to methods of creativity / invention / problem solving. In contrast to TRIZ, PEM uses techniques such as brainstorming, forced analogy, and many other tools. When people are thinking about wacky methods of being more creative, they usually are thinking about one of the PEM tools.
We (BIG) feel, with all due respect to Altshuller (TRIZ guy), that PEM does in fact have a place in creativity and invention. We have applied it quite successfully, in conjunction with TRIZ, especially in the early stages of ideation.
PEM tools work well in a team environment where people can have fun. Kinda sounds like us, doesn’t it!
TRIZ is a Russian acronym: теория решения изобретательских задач, or transliterated as: teoriya resheniya izobretatelskikh zadatch. It generally is translated as the Theory of Inventive Problem Solving. So, at times it has been called TIPS. But this makes it sound like just a bunch of suggestions, so real TRIZ people don’t like that name. By the way, it sounds like “trees”. Not like “tris”.
TRIZ was mostly developed by Genrich Altshuller during the mid-late 1900’s. The goal of TRIZ is make invention more of a science; more of a process. In fact, Altshuller developed what is called ARIZ, which is an algorithm for inventive problem solving!
Quite a lot of the core of TRIZ is around solving contradictions. Altshuller generally considered tools like brainstorming to be too divergent, and a waste of time. He wanted to get down to the solution fast, and reliably!
Some of the body of knowledge of TRIZ is not used so much. However, some of it is fundamental solving contradictions.
Altshuller also had an interesting life. I would recommend one his early books titled, “And Suddenly the Inventor Appeared”.