“We’re doing Lean + Six Sigma!” The look in his eyes was confident, with a hint of smugness.

I knew what I was supposed to say... “Well, then, you’re at the leading edge, doing all you possibly could be doing for your organization.” But I’m a poor liar. I couldn’t say that with a straight face. I just sighed and said, “I hope it helps.”

When a hot method becomes the buzz, there are people who think it’s the answer to everything. That causes two problems: One, other important initiatives are displaced. And two, the method is applied to problems it was never meant to solve. When this happens, it can do as much harm as good.

Lean and Six Sigma are two distinct organizational improvement methods that are being combined into an organizational streamlining program. Each has its capabilities and its limits. Let’s take a rational look at Lean + Six Sigma and get a perspective on what they are, and are not, supposed to do.

Lean
The Lean method (short for Lean Manufacturing) is a modern version of an old tradition—business process reengineering (BPR). It’s a method to redesign, and hopefully optimize, a workflow and reduce waste. Originally, it focused on seven ways to reduce waste in manufacturing (transportation, inventory, motion, waiting time, over-production, processing efficiencies and defects). In addition to its reengineering roots, Lean employs kaizen style project management—week-long blitzes and quick experiments that speed the process.

All reengineering processes have their origins in a method pioneered in coal mines in the late 1940s by the Tavistock Institute in Great Britain. The method, called “socio-technical systems analysis” (STS), engaged those doing the work in rethinking how the work is accomplished. STS guides workers to design a fresh approach to both the technical system (steps and work-processes) and the social system (communications and coordination).

James C. Taylor (in the United States) and Enid Mumford (in the U.K.) pioneered the application of STS to white-collar work. A few years ago, I spoke with Dr. Taylor about STS and the many subsequent reincarnations (including BPR of the 1990s and now Lean). Too polite to criticize the work of others, Jim described the key lessons of STS that we can use to evaluate newer methods.

First, participation is essential. Many of the recent methods look more like Frederick Taylor’s “scientific management” and 1950s-style industrial engineering, where so-called “experts” redesign processes with little more than token participation from the workers who know how things really get done.