The Principles of Product Development Flow

Reinertsen sets out a large collection of numbered principles for managing the flow of product development work, grounded in queueing theory, economics and control theory. The central argument is that development is dominated by invisible queues, and that cost of delay gives you one economic measure for making sequencing and batch size decisions. The chapters move from the economics of a development pipeline through queueing behaviour and variability, and on to batch size, work in process constraints, cadence and decentralised control. It is dense and mathematical in places, and it is the source most scaled frameworks draw on for their flow material. Read it when the argument about how much work to start needs evidence rather than opinion.