Six Sigma Meets Lean

Six Sigma Explained

You will hear the term constantly in operations consulting. A Six Sigma process is one that produces only 3.4 defects per million units, which means it is almost perfect. Motorola coined the term in the 1980s and General Electric (GE) made it famous. Jack Welch, the former chief executive officer of GE, took Six Sigma to a different level, and at one point the company hosted more than 8,000 Six Sigma-related pages on its corporate website. If GE makes an engine, it wants that engine to behave exactly like the one before it. The company achieves this reliability by continually whittling down the factors that create different outcomes until the process reaches Six Sigma consistency. With Six Sigma, the consultant thinks constantly about reducing variability.

Variability Is Usually Bad

The idea that processes should be consistent is neither radical nor untrue. When you know something works, you should repeat it rather than spend time and energy reinventing the wheel. Best practices rest on the assumption that time-tested, successful processes can be replicated with little controversy or alteration. This logic explains why Enterprise Resource Planning (ERP) exploded in the 1990s ahead of the year 2000 systems upgrades. Companies bought into the idea that they could standardize their most routine operational and financial processes in line with what SAP and Oracle had designed for hundreds of competitors.

Standardization works in high-stakes environments too. The adoption of pre-flight checklists in aviation and surgical checklists in hospitals provides one of the most famous examples in recent history. Pilots and surgeons once ruled their domains like kings, and both resisted standardization as an insult to their expertise. That attitude is changing. Atul Gawande wrote The Checklist Manifesto about how something as simple as a checklist saved patient lives at Johns Hopkins, one of the premier hospitals in the world. 1 shows that a 19-item, two-minute checklist reduced surgical deaths by 47 percent across eight hospitals worldwide. At a high level it makes complete sense to standardize the boring, low-value-added parts of your business. If a process does not actually make you better than your competitor, spending extra time or money on it is waste.

Does Six Sigma Apply to Consultants

Yes. If you have boring, low-value-added parts of your business that need standardization, this applies to you. Lawyers, accountants, digital marketers and everyone in between benefit. Squeeze the variability out of routine work and you become more efficient. Brainstorm through the activities in your workday that improve when done exactly the same way every time. Those are the targets for vigilant Six Sigma discipline. Ask a simple question: why are we doing that boring thing five different ways? The culprits often include inconsistent filing nomenclature, poor version control, missing templates, unclear branding instructions, irregular expense tracking and ad hoc interview processes that produce uneven hires.

The payoff is measurable. When a firm standardizes its proposal templates, it shortens turnaround time and frees senior consultants to focus on the client-specific analysis that actually wins work. When it enforces consistent interview rubrics, it reduces hiring mistakes and improves retention. Each of these improvements removes variability from a process that does not differentiate the firm, which channels energy toward the work that does. The principle is simple: standardize the routine so you can innovate on the meaningful.

Limitations of Six Sigma

For all its hype, Six Sigma has real detractors and legitimate criticisms. Analysis paralysis is the first trap, because a poorly scoped effort encourages over-analysis using regression models and statistical tools that only the geekiest MBAs enjoy. Steady-state assumptions pose a second problem, since Six Sigma tries to control a process it assumes is stable. Disruptive thinkers agree that we live in a non-linear world where the average means little. Short-term focus is a third weakness, because Six Sigma aims to reduce variance and get a process under control. Sameness delivers dependability but discourages breakthroughs. Process dogma is the fourth issue, and as leadership speaker Andy Stanley notes, an organization's purpose should not change but its processes should always change. 2 confirms that the firms achieving the biggest gains pair an upfront diagnostic with disciplined deployment, not rigid adherence to a single toolkit.

Professional Services Operate Differently

Few things in professional services reach Six Sigma reliability. Oil pipeline pressure and stitch counts in jeans qualify, but client problem-solving does not. Consultants are not robots, nor should they be. Clients pay for solving problems that technology, outsourcing or inaction cannot easily handle. A lawyer competing with LegalZoom is in trouble. A consultant assembling mindless slide decks is in trouble, because freelancers will do it for a fraction of the cost. Professionals earn their fees by solving complex problems, not merely controlling a process. Reduce the variability in the boring parts of your work to free time, freedom and margin for the innovation that delivers real client value.

The distinction matters because clients can tell the difference. They do not pay premium rates for work that a template or a junior analyst could produce with a checklist. They pay for judgment, pattern recognition and the ability to navigate ambiguity. A consulting firm that standardizes its back-office operations while preserving space for creative problem-solving on the front end delivers both consistency and insight. That balance is the hallmark of a mature professional services practice.

Lean Completes the Picture

Consulting firms combine Lean with Six Sigma to capture the best of both worlds. Lean focuses on value through simplification, while Six Sigma focuses on quality through repeatability. Bain found that three-quarters of Six Sigma projects failed to reach their savings targets when deployed in isolation. The real question for consultants is whether they apply the same diligence to their own proposal creation and client delivery that they push onto clients. In other words, are you eating your own Lean Six Sigma dog food? Do you practice what you preach? 3 summarizes the waste categories Lean targets: transport, inventory, motion, waiting, overproduction, overprocessing and defects. Eliminate those wastes, standardize what remains and you build capacity for the work that truly differentiates your practice.

• 1The Checklist Manifesto and how surgical checklists cut mortality by nearly half
• 2Bain and Company on how Lean Six Sigma drives plant performance and cuts costs
• 3The seven wastes of Lean, known as TIMWOOD