The authors contend in this phase that once the constraint has been identified, it needs to also be isolated so that controllable and uncontrollable areas can be defined. The control mechanism, often called a buffer, shields the constraint from extraneous effects and other variables so that strategies can be defined for minimize constraint variation first, and eventually externalizing the constraint (Lepore, & Cohen, 1999). Buffers often are managed to a series of metrics or key performance indicators to assure that any external factors or forces are not significantly influencing it over time. The greater the variability in a constraint the greater the need for a buffer to be agile and capable of shielding the constraint from the effects of extraneous factors so approaches can be found to minimize it (Lepore, & Cohen, 1999). This is an essential step for eventually minimizing constraint variation and externalizing it. The authors clearly are experts on this specific topic as they provide a wealth of insight and intelligence on how to achieve greater reliability, dependability, consistency, quality and performance when constraint variation is minimized. This is also one of the most focused areas of the book on how to overcome resistance to change. Getting those most involved with the change to own the process modifications by giving them a voice in how they are accomplished, defining strategies for overcoming the six layers of resistance to change (Lepore, & Cohen, 1999) are all crucial if long-term change is to be achieved.

The most pivotal phase and most difficult for organizations to adopt is the seventh one as it requires a shift away from the traditional hierarchical model to a more schematically driven one. This is also the phase where the authors point out the strengths of the Deming Theory of Profound Knowledge having interactions and dependencies defined (Park, Ntuen, Park, 2009). The authors point out that the Deming concepts actually undermine the value of a traditional hierarchical structure because it does not take into account the many interdependencies and integration points external to the organization. In effect a hierarchical structure is one that does not fully explain the potential influences on constraints over time (Lepore, & Cohen, 1999). The authors use this point...

With the next step being the eliminating of the external constraint, the use of TOC Thinking Process Tools is used in an example of the irresfuable marketing offer, the analysis first addresses the core problem of the customer, does not necessarily demand they change, but that the suppler does, and eventually forces a supplier to break policy constraints. The supplier gets a price exception increase as a result of their extra effort. The irrefusable marketing offer is a recurring example the authors used to put the TOC Thinking Process Tools into context (Lepore, & Cohen, 1999). It also is a useful construct for illustrating how to move a constraint within an organization to fix it, which is the ninth step in the process the authors define. The use of the TOC Thinking Process Tools also serves to make the constructs and framework of the book applicable to non-manufacturing processes as well. It also sets the foundation for the final phase, which is setting up a continuous learning program. The authors integrate the Deming Cycle for continuous improvement (PDCA) with the TOC to create recommendations for how organizations can overcome resistance to change and increase accuracy and speed of transactions as a result.
Conclusion

The integration of the Deming System of Profound Knowledge and Dr. Eli Goldratt's Theory of Constraints provides this book with a solid theoretical foundation the authors have crated a pragmatic platform on. The most difficult aspects of externalizing constraints are well defined and actual examples given. The use of the TOC Thinking Process Tools also illustrates how the concepts in this book can just as easily be applied to non-manufacturing; services-based businesses and strategies as well. By seeking to minimize and eventually alleviate the variation in constraints, the authors accurately show how processes can be made more accurate and efficient over time.