Book Review: The Principles of Product Development Flow: Second Generation Lean Product Development

    By: PDMA Headquarters on Oct 04, 2013

    Book Review: The Principles of Product Development Flow: Second Generation Lean Product Development 

    By: Donald G. Reinersten, Redondo Beach, CA : Celeritas Publishing , 2009 . 294+ix pages  
    Review by: Katherine Radeka

    Book ImageThe Principles of Product Development Flow continues the work that Don Reinertsen began with Managing the Design Factory (1997) to apply queuing theory to the complex problem of managing the flow of work through product development. In this new book, Reinertsen extends his earlier ideas with military strategy, control engineering, and telecommunications management practices to provide a comprehensive assessment of the dynamics of flow and control in product development.

    This book explains in great detail why systems like the Toyota Product Development System (TPDS) work so well to improve flow in product development. Reinertsen delves into the mathematics behind core ideas such as Little's Formula and options pricing theories to derive principles about how to increase economic value in product development. He explains why the Internet is a better model for managing product development than the factory and how the cost of delay assumes strategic importance in an organization committed to optimizing product development performance.

    Reinertsen advocates less emphasis on product development cycle time, or time-to-market metrics, to bring queue lengths, batch sizes, and waiting times to the forefront. He shows how these leading indicators of delay can help a development organization spot problems early before they have the opportunity to become big problems (pp. 259–260). The author provides ideas for how to manage these metrics, including cross-training to develop people who have more flexibility to help out overloaded experts (p. 156) and better criteria for making product development portfolio decisions (pp. 42–44). He explains why the economics of product development works against eliminating all variability from product development (pp. 86–94) and how to determine the optimum amount of risk that a product development program should have to deliver maximum economic value (pp. 50–51).

    The book's main strength is Reinertsen's willingness to delve into the complexities of the theories to provide conclusive proof for his recommendations. Product developers, especially engineers, often need this deep understanding to help them recognize the need for change and decide to try new things. For those who have a scientific background, Reinertsen's intellectual rigor with respect to these ideas will satisfy their need to understand why conventional wisdom about product development so often leads to poor performance and how counterintuitive practices such as cutting batch sizes leads to speed and lower cost at the same time.

    The book's major flaw is its unwillingness to acknowledge the work that anyone else has done with these ideas in product development. Agile software development has an entire body of work devoted to cutting development batch size. The branches of lean product development that have their roots in TPDS also provide compelling examples of how his ideas for managing variability and risk have worked in practice.

    Instead, Reinertsen takes a derisive tone toward agile software developers, Six Sigma practitioners, and other lean product development researchers, to the detriment of his arguments for readers who already understand those concepts better than he appears to. He repeatedly misses opportunities to draw connections between the arguments that he puts forward in theory and the ways that others have shown these ideas to work in practice. For example, he explains why the agile practice of iterative development cycles work (p. 135), but if the reader was unfamiliar with the concepts, there would be no guidance and therefore no learning about how to implement such a scheme effectively. In fact, the agile software community has a great deal of experience with limiting batch sizes and work-in-progress (WIP) using iterative development cycles, but the reader would have no way to know that based upon this book and because no references are provided for further learning.

    The author subtitled this book Second Generation Lean Product Development, although it makes scant reference to the TPDS and seems to argue against some of the fundamental ideas embedded within Toyota's approach to product development. For example, he chides lean product development teams for waiting until the “last responsible moment” to make decisions. In fact, he fails to recognize that he is in violent agreement with Mary Poppendieck, the author who pioneered this concept in her book Lean Software Development(Poppendieck and Poppendieck, 2003). The very point in time where he advocates making decisions is the same as hers: the point in time where the cost of delaying the decision exceeds the potential benefit from delaying the decision further (pp. 44–45).

    He also misconstrues set-based concurrent engineering (SBCE) to mean parallel path development (p. 49), which is a misconception debunked in Sobek, Ward, and Liker's (1999) original paper describing the concept. He then makes a compelling argument for following the process of SBCE as described in that original paper two chapters later (pp. 105–109). He could have enriched his own argument by employing the research that shows the benefits of SBCE rather than dismissing it off-hand, which makes it seem like he has not completely done his homework.

    This book is best for scientists and engineers who have recently transitioned into product development process management roles and who desire to deeply understand why agile software development and elements of lean product development deliver improvements in product development cycle time and increased capacity to deliver new products. They will appreciate the author's willingness to dive into the mathematics behind iterative development, which limits batch sizes and actively manages designs in process, and into the applications of telecommunications network theory to the realm of product development.

    This is also a great book for anyone in an operational excellence role, such as a Six Sigma Master Black Belt, who is assigned to work with research and development organizations. Reinertsen takes frequent detours to explain why the fundamental principles of the Toyota Production System, the source of lean manufacturing, and Six Sigma break down in the high-risk, high-reward arena of product development. He provides alternative strategies for optimizing the product development process along with the logical and mathematical proofs to debunk the typical Lean Six Sigma approach to product development.

    For others, including most product development managers, Reinertsen's work is a good source of arguments to bolster the case for fundamental changes in product development processes but is not necessarily a good source of advice on how to implement those changes. For example, he says almost nothing about effective portfolio management, leaving others to derive effective portfolio management practices from his descriptions of economic values, queues, and flows. The pieces are all there, but they are not connected together into a consistent framework. A product development process improvement team will have little guidance about where to focus first.

    In reality, there are many good, practical guides to product development that give specific advice about how to increase throughput that will lead to dramatic performance increases. Readers who need to improve their product development processes and who lack patience for detailed explanations of theories will find one of those books to be a better fit for them.

    Released: October 4, 2013, 10:11 am | Updated: November 20, 2013, 10:44 am
    Keywords: PDMA Blog

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