1. Reducing waste, where waste is anything that doesn’t add value for customers.
2. Creating value for customers — and doing nothing that doesn’t truly add value.
3. Making the company more flexible so it can respond quickly to new customer needs.
Six Sigma aims to eliminate defects by driving down variation in processes, finding the best process and then making sure it gets used everywhere and all the time. But an excessive focus on eliminating variation can reduce flexibility and innovation, as it may mean that customers get crammed through the same process even when they don’t have the same needs. Lean brings a healthier focus on process improvement that places the customer at the center. This approach avoids eliminating too much variation, thereby retaining the flexibility that is often the key to competitive differentiation, superior customer service, and product innovation. Lean is for everyone while Six Sigma is for Green Belts and Black Belts mostly alienated from the rest of the company. And thats why we think that Lean fits in well with Scrum & XP.
Lean is also how we touch base with processes in a company. While Scrum & XP are Engineering focussed we connect our clients IT teams to the Business using Lean and help them evolve from IT to Business Technology. The focus for Agile is really about reducing waste: Continuous integration and build reduces waste, TDD reduces waste, better collaboration reduces waste, and so on. But reducing waste is only half of the Lean picture: To be Lean in the fullest sense, organizations must also focus on adding value.
Lean is the exact opposite of bloat. Bloat kills. Whether it’s excessive complexity in the application, its underlying platform or architecture, or the process used to deliver it, overloaded platform software and heavy processes impede delivery of the solutions the business demands. Yet most enterprises are awash in application suites, development tools, processes, and platforms that have grown so large they no longer resemble the clean and clear vision of their original purpose. Lean Software is emerging as the antidote to bloatware, enabling architects and developers to rapidly assemble business solutions that deliver “just in time” the software capabilities the business requires both today and tomorrow. The trend toward Lean Software has been building for years, but the worldwide recession is accelerating it. All application development professionals should know why and how to incorporate Lean Software into their software strategies for the future. We "Design for People" and "Build for continous change". Agile methods are at the heart of process change, and we are seeing the result in the way people build software, whether the changes involve continuous integration and build, test-driven development (TDD), the use of wikis for documentation, or software deployment. When shops need to deploy software more frequently, rigid, complex, and difficult-to-execute processes have to disappear. The aim of all these technologies and practices is eliminating waste from a project — a key tenet of Lean Software.
# Some text quoted from Forrester Review