Bulldozer00's Blog

Obviously, even the most iterative agile development process marches forward in time. Thus, at least to a small extent, every process exhibits some properties of the classic and much maligned waterfall metaphor. On big projects, the schedule is necessarily partitioned into sequential time phases. The figure below (Reqs. = requirements, Freq. = frequency, HW = hardware, SW = software) attempts to model both forward progress and iteration as a function of time.

If the phases are designed to be internally cohesive, externally loosely coupled , and the project is managed correctly, the frequency of iteration triggered by the natural process of human learning and fixing mistakes is:

• high within a given project phase
• low between adjacent project phases
• very low between non-adjacent project phases

Of course, if managed stupidly by explicitly or implicitly “disallowing” any iterative learning loops in order to meet equally stupid and “aggressive” schedules handed down from the heavens, errors and mistakes will accumulate and weave themselves undetected into the product fabric – until the customer starts using the contraption. D’oh!