Garrett, here. I wrote and produced all of this by pulling together and distilling insights from a handful of key books and research papers on software development, project management, and QA. These included sources like The Pragmatic Programmer, Code Complete, The Art of Software Testing, and others. I love this topic and would be happy to discuss and answer questions about it. The short version of it is that it shows the cost effectiveness of investing in code and software quality and provides a simple roadmap for a team to evolve and improve their process as they add more advanced capabilities into their development, testing, and release practices.