How does this study relate to software development? There are significant differences between turning out identical widgets and developing software, a creative endeavour producing different products each time. In fact, author Mary Poppendieck notes in the preface of Lean Software: An Agile Toolkit for Software Development Managers that CMM (Capability Maturity Model) and PMI (Project Management Institute) methodologies, with their heavy emphasis on process definition and detailed front-end planning, borrow heavily from the lean manufacturing movement. These methodologies are in some ways diametrically opposed to Agile principles, and yet Poppendieck and other writers and teachers of Agile methods continue to find valuable lessons in manufacturing process theory.
David J. Anderson's article Feature-Driven Development: towards a TOC, Lean and Six Sigma solution for software engineering from 2004 seems to connect the dots, for those new to the subject. Anderson uses ideas from these disciplines in his work. Anderson is the author of Agile Management for Software Engineering: Applying the Theory of Constraints for Business Results.