Lean or Six Sigma: the Progress Paradox

If you're talking basketball and you want to spark passionate debate, ask the question: Who's the best ever—Michael Jordan or LeBron James?

If you're talking continuous improvement and want to spark equally passionate debate, try this question: Which is better—lean or Six Sigma?

In this episode of Behind the Curtain: Adventures in Continuous Improvement, podcast hosts Dr. Mohamed Saleh and John Dyer take on the topic of lean versus Six Sigma, discussing the merits of each and the ways that organizations use, or misuse, them.

Saleh is quick to claim the debate is completely flawed. While lean is a management philosophy and operating system, Six Sigma is a problem-solving methodology, he argues.

“Lean is built on things like respect for people, flow, problem visibility, learning at the source, leadership development,” Saleh says. “These are, for me, key points, [about] how should an organization be designed and led … not just how should a problem be solved.”

“For me, lean is a principle-based architecture,” he adds.

Dyer pushes back on Saleh’s characterization of Six Sigma, while agreeing that lean has a more “philosophical slant to it … if the people who are doing lean do it the right way,” he adds.

“A lot of times people will implement 5s and that's it, and say, ‘Oh, we're doing lean,’ or they'll do a few other tools like value stream mapping and say, ‘Oh, we're lean,’ when they haven't adopted all the different philosophies,” Dyer says. “They're still doing command and control. They're still doing firefighting. They haven't empowered their teams, and in that regard, I would say that they're not doing lean. They're just doing … a few tools of lean.”

Organizations’ deployment of Six Sigma does not emerge unscathed, however.

“There is a woeful lack of understanding of how variability impacts processes, and that's what Six Sigma was meant to help promote,” Dyer notes. He wonders aloud how many green-belt or even black-belt certified individuals could do a capability study six months after they have been certified.

The duo also dives into:

• How Six Sigma’s DMAIC (Define, Measure, Analyze, Improve, Control) approach compares to lean’s PDCA (Plan, Do, Check, Act) and A3 problem-solving tool.
• Where Lean Six Sigma fits into the discussion.
• Whether lean and the Toyota Production System are the same thing.

Do Saleh and Dyer conclude this episode by putting the lean and Six Sigma debate to rest? Listen in to find out. However, on two points there is no dissension. First, a tools-based system is not the route to long-term success, they agree, and second, the importance of culture cannot be overstated.