Improvement Insights Blog

What’s the main bottleneck to Six Sigma? I think the answer will surprise you:

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“Hi, I’m Jay Arthur, author of “Lean Six Sigma Demystified” and QI Macros [software].

“It’s January 2, 2026. And I don’t know about you, but Six Sigma is still moving way too slow. One of the things I thought about was, “Maybe you can use the theory of constraints to talk about why that is and what we can do about it.” I’ve been doing this for 35 years now, and I keep wondering why isn’t anything any better? I think some of it is, but I think we could be going a lot faster.

“So what’s the Theory of Constraints? Well, the Theory of Constraints says that in any process, there’s always one thing that’s kind of a bottleneck, right? So, there’s a bottleneck that slows everything down and everything else has to be paced to handle the speed of the bottleneck. Does that make sense? What’s the bottleneck in Six Sigma? I’m going to argue it’s the training process we have chosen.

“Way back in the 1980s when Mikel Harry and company figured out how to do this at Motorola, they came up with this whole plan. Now, I was just rereading his book. Guess how long he says it takes to mint a Black Belt? 24 weeks. That’s a half a year. Then he says it’s going to take two or three projects before that Black Belt gets proficient at things before they can tackle more complicated things like DOE and so on, right? So they’re going to have to do multiple projects. But then he admits that very often they don’t do two or three projects; they do one, maybe two, then they get promoted or they get poached by some other company. How are we going to make any progress like that?

“So there are different kinds of constraints. There’s policy constraints like ‘We’ve always done it that way.’ Well, I want you to consider that we’ve always done Six Sigma the same way: Two- to four-week training spaced over months… and guess what? We’re not getting there.

“What can I suggest? Well, I started back in 2000 using what I now call Agile Lean Six Sigma or Agile Process Innovation where we can start getting results in a day or two. We’re only training people in basic Yellow Belt stuff. You know, I call it MVT, Minimum Viable Training… Minimum Viable Training. Don’t teach people things they don’t need to know to solve problems they don’t have to impress people they don’t like. Let’s get them going on projects that need solving and that they can solve quickly using available data. You don’t have to go mint new data. That’s stupid, right? There’s a lot of data sitting around, especially about things that are really a problem.

“Now, that sounds horrifically insane to most people, you know, but that’s our problem. ‘We’ve always done it that way.’ Maybe there’s a better way to do it. I’ve been doing it for the last 25 years. And in the recent five or six years, I’ve seen other companies tell about how they had to go out and figure out how to do it in one or two days. Guess what? You don’t need to. I’ve figured that out.

“I have a free Yellow Belt training at www.lssyb.com, so you can go out and send anybody to that. You know, I saw a presentation by Underwriters Laboratories. They have people all over the world and so they built their own kind of online training which people will go through for a day and then they’d meet locally as a team to solve a problem. You don’t need to do that; I’ve already got one. There’s already a Yellow Belt training sitting out there for manufacturing and healthcare; it covers service and manufacturing.

“In Mikel Harry’s book, he talks about in manufacturing, 90% of the people employed in manufacturing are in the service side of the business: orders, purchasing, payments, whatever. They don’t need all these tools… they don’t; [that’s] Minimum Viable Training. Maybe there’s a way to go about it. I also put up an Agile Lean Six Sigma Trainer Training which you can take for free, and this year I’m going to add a certification to that so you can get certified by taking the Yellow Belt [training and] the [Agile Lean Six Sigma Trainer Training] and then going out and teaching your own class, right? And then sending me an improvement project that matches what I think a really good improvement project should look like. It’s not fancy: control chart, Pareto chart, fishbone, control chart to sustain and monitor and track what’s going on and make improvements if something goes wrong. This is not hard, but we have to unlearn some crap that we have learned over the years about how Six Sigma is implemented.

“Now the other thing about this that I want to point out is this makes implementation easy. There’s a book called The Diffusion of Innovations and Diffusion of Innovations says when you get as little as 4% of a population doing something it will stick in a culture. Now this matches my 4-50 rule. If you take 4% of your business, that’s causing over half the mistakes, errors and waste and rework, guess what? You can focus teams on solving those problems and you’re going to get 4% of your people doing it and then you can do the next 4% and the next 4% and the next 4%. The Diffusion of Innovations says [with] somewhere between 16% and 25% adoption, it spreads throughout the whole environment.

“So instead of having these big training things: you know, where we start big with champion training and Black Belt training, and the Black Belts have to train a hundred Green Belts. (That’s what Mikel Harry said in his book: every year… I don’t know if you can do that much training in one year.) Anyway, instead of doing it that way, what if we do it this way where we train some Yellow Belts and get some results and train some more Yellow Belts and get some results? And out of those initial teams, you’ll discover people who really have the interest, the drive, the desire to go out and be a Green Belt, a Black Belt, a Master Black Belt. Invest in those people because when you start, you have no idea who’s going to want to do this and be good at it. You just don’t, right? People will show up because they want to add it to their resume. Well, that’s not a good reason for the company.

“So, that’s my Improvement Insight. Let’s go out and improve something this week, like how we train and implement Six Sigma so we can start getting results quickly. Then take the people that are really good at it and move them on into Green Belt and Black Belt training to the point where it kind of takes over as the way we do business.

“Let’s go out and improve something this week.”