Eliyahu M. Goldratt was the creator of the Theory of Constraints (TOC), introduced in his 1984 novel "The Goal." Goldratt and Reinertsen offer complementary approaches to flow optimization in development systems.
Goldratt's TOC focuses on identifying the system constraint (the bottleneck that limits throughput) and relentlessly exploiting and elevating it. Reinertsen's approach focuses on the economics of the entire flow system — optimizing trade-offs across cost-of-delay, batch-size-reduction, wip-constraints, and u-curve-optimization. Both argue forcefully against local optimization and for systems-level thinking; both use manufacturing-derived metaphors to illuminate knowledge work. Reinertsen's wip-constraints overlap significantly with Goldratt's drum-buffer-rope scheduling approach, though Reinertsen derives his recommendations from queueing-theory-applied rather than constraint theory. Where Goldratt asks "what is limiting throughput?", Reinertsen asks "what are the economic trade-offs in the flow system?" — different entry points that often lead to similar operational conclusions.