The Art of Lean Software Development

Other Complementary Approaches

There are some complementary business management strategies whose methods and techniques are often combined with (or used by) Lean. As you read the literature on Lean, you’ll run into these methods repeatedly. We won’t discuss them in detail in this book, but we want to give you the basics so that you’ll recognize them when you see them.

The ones you’ll hear about most often are the Theory of Constraints (abbreviated as ToC), Critical Chain (ToC’s engineering counterpart), Six Sigma, and Capability Maturity Model Integration (CMMI).

Theory of Constraints

ToC and Critical Chain (CC) are the brainchildren of Dr. Eliyahu Goldratt. They are based on a few simple principles and a set of problem-solving processes and tools for improving a business process (which includes the process of developing software). ToC and CC are based on the idea that at any given point in time there are one or more constraints limiting the performance of the overall process.

The tools and methods of ToC and CC are designed to help you identify these constraints and then remove them. This, of course, changes the system and results in new constraints. In the spirit of continuous improvement, this process of finding and removing constraints is applied repeatedly.

Once you start reading about ToC and CC, it is easy to see the parallels with Lean. There is currently a little bit of industry talk about applying ToC and CC to software development, but there are no serious efforts that we ...