There are various terms out there for process improvement. Here's an overview of what they mean.
Six Sigma was created at Motorola in the 80s. Six Sig is about:
- top-down control
- error reduction through measurement
- promotion of Six Sigma
Six Sigma measures quality but doesn't embody any strategies to improve quality, so it's often bundled with Lean and sold as "lean Six Sigma".
Kaizen is a shorthand term for the body of thought that came out of the Toyota Production System (TPS), which was created primarily by the Toyoda family and Taiichi Ohno after WWII. Kaizen is about:
- continuous improvement ("kaizen")
- smooth and even flow (Just In Time)
- respect and enablement
Lean is a major and very useful subset of Kaizen (TPS) which deals with reducing waste. Identifying waste (like wasted time, waste through defects) is a great way of identifying potential improvements.
Reengineering was created by an MIT computer science professor called Mike Hammer in 1990. It's really about lateral (discountinous) thinking, and its focuses are to rethink and to aim for the goal.
- Rethinking existing processes: What do you *really* want to do? For example, the business might ask for more efficient and accurate invoicing. But why automate invoice production if you can avoid invoices?
- This rethinking and aiming for the goal tends to realign processes, teams and systems around end goals. For example, cars were made one at a time by small teams of artisans until Henry Ford created the production line.
- Remove the division between strategy and tactics. Align end-to-end on what works.
Hammer lists a toolbox of common reengineering outcomes (like case management, mass customisation), but the reengineer shouldn't be distracted by these.
Reengineering is a mindset, it's not a substitute for an improvement methodology like kaizen.