One of the principles of the Declaration of Interdependence is that Agile Project Management "... increase(s) return on investment by making continuous flow of value our focus." Sounds great, I want that.
- How is value defined?
- What are the units of measure for "continuous flow?"
- Is ROI the proper model for value measurement?
One place to look for some real world discussion of the economic of engineering projects (I'll assume that the DoI is applicable to engineering projects) is a journal The Engineering Economist. It's contents can be found at the Find Article search engine http://www.findarticles.com/p/articles/mi_qa3621
From there you can look around and see what is being discussed by those tasked with delivering on the goal of "continuous delivery of value." There are a broad range of topics ranging from formal finance to the economic of paired programming.
I came across this site and the journal in my research of probabilistic risk analysis of project schedules. It's a treasure trove for those of us with an analytical bent or simply part of our job requirements.