The most dangerous moment in Lean is often right after your first belt class–when you think you've mastered it all.
You may have seen the joke image that I posted on LinkedIn:
“I'm an expert in Dunning-Kruger syndrome!”
The humor works (I think) because the Dunning-Kruger effect describes how people with little experience in a skill often overestimate their competence. In Lean and continuous improvement, this shows up more often than we'd like to admit–especially right after your first Lean belt certification, your first Lean course, or your first Lean book.
Those early “aha” moments are exciting, but without ongoing practice, coaching, and feedback, that enthusiasm can quickly turn into one of the most common Lean training mistakes: believing you've already mastered it.
You can't improve a skill you believe is already perfected.
I've seen this in many forms. Sometimes it's after a Green Belt course. Other times, it's after a two-day Lean workshop, a single site visit, or reading that first Lean book that really clicks. The danger isn't in the excitement–it's in the assumption that excitement equals expertise.
When people are so certain of their expertise that they stop inviting challenge or seeking a second perspective, they risk becoming trapped in their own certainty. That's dangerous in any improvement work, where curiosity and humility are essential.
Why Your First Lean Belt or Book Isn't the Finish Line
Great leaders go beyond giving feedback. They create psychological safety–a climate where feedback flows in all directions, without fear of embarrassment or retaliation.
In that environment, reality has a way of breaking through overconfidence. Assumptions get tested. Blind spots are revealed. And people stay open to learning, no matter their level of experience.
The goal isn't to crush confidence–it's to anchor it in reality so it can stand the test of time.
Practicing Lean: Learning from Early Mistakes
In Practicing Lean–a book I wrote with 15 other contributors–we reflected on our own early Lean journeys. We all had a starting point, and looking back at those first months or years, we probably weren't very good at it. I know I wasn't.
“When I first learned about Lean, I thought it was about tools and projects. It took me years to realize it was really about people and culture.” — Mark Graban
The book's premise is simple: doctors don't “implement medicine,” they practice medicine. Lawyers don't “implement cases,” they practice law. Shouldn't Lean facilitators, consultants, and managers also practice Lean?
Across industries–manufacturing, healthcare, software, startups–contributors shared mistakes made, lessons learned, and how their practice evolved.
“I didn't fail because Lean didn't work–I failed because I didn't yet understand how to work Lean.” — Katie Anderson
We all shifted from “doing Lean” to “being Lean,” and eventually, to teaching others how to be Lean. That journey is never finished.
“Looking back, I thought I was teaching Lean. In reality, Lean was teaching me.” — Jamie Flinchbaugh
If we keep practicing, we might get good at it… eventually. It's not guaranteed. Having a great coach helps. Having a growth mindset helps.
How to Avoid Common Lean Training Mistakes
To steer clear of the Dunning-Kruger trap in Lean:
- Treat certifications and courses as starting points, not destinations.
- Seek out feedback continuously, especially from those with different perspectives.
- Create (or find) environments where it's safe to admit what you don't know.
- Reflect regularly on how your thinking and practice have evolved.
Continuing the Learning Journey
One more note: 100% of author royalties from Practicing Lean continue to be donated each month to the Louise H. Batz Patient Safety Foundation, a non-profit dedicated to helping patients and families avoid preventable medical harm. The stories in this book are about learning from mistakes–and this cause is about preventing the most serious ones.
Because if you think you've “arrived”… you've probably just missed your exit.
What about you? When you look back on your Lean journey, what was your “first belt” moment–or your first Lean course or book–and what have you learned since then?
Please scroll down (or click) to post a comment. Connect with me on LinkedIn.
Let’s build a culture of continuous improvement and psychological safety—together. If you're a leader aiming for lasting change (not just more projects), I help organizations:
- Engage people at all levels in sustainable improvement
- Shift from fear of mistakes to learning from them
- Apply Lean thinking in practical, people-centered ways
Interested in coaching or a keynote talk? Let’s talk.
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