Monday, November 10, 2003

Why Agile is not Lean?

Business Week examines the power train of Toyota and wonders if anyone can stop them? The article provides good insight to the advantage that comes from 50 years of developing just-in-time inventory systems, Deming quality assurance, designing out the possibility of failure and a process of continuous improvement.

There are 4* main aspects to Lean Production: Kanban (the notion of self-organizing flow regulation); Kaizen (the process of continuous improvement); Quality Assurance (Edwards Deming’s teachings on Statistical Process Control); and Pokayoke (the notion of designing out failure). [* As Hal Macomber points out , in the comments, this list should have included Muda (waste) as the 5th key element]. So far agile software methods have really only developed in two of these areas - self-organization and quality assurance. Despite the feedback loops in agile methods, they are primarily quality assurance loops not learning organization loops. And there is really no equivalent of Pokayoke in agile methods. In fact, early writings on agile methods suggested that tools were not important. There was an almost Luddite tendency to ignore tools and focus only on people.

The closest thing to Pokayoke in agile is the design and code inspections in FDD. However, these don’t go far enough. Proper Pokayoke would be using architecture and tools which design out the possibility of failure. Tools such as Statesoft’s JStateMachine represent “pokayoke for user interface”. A fully Lean software development method will include architecture, modeling and supporting tools.

My final word on this Toyota article is the observation that Toyota is a “failure tolerant” company which has transcended beyond a mere “learning organization”. Those familiar with Chapter 11 and 12 of Agile Management for Software Engineering will understand this. My proposal for an agile maturity model calls for a learning organization as level 4 and a failure tolerant organization as level 5. Toyota is clearly a level 5 organization on that scale.