Experiences with the spiral model as a process model generator
BARRY W. BOEHM, Frank C. Belz · International Software Process Workshop · 1989
A good many of the problems on software projects arise from mismatches between the process model used by the project and the project's real-world process drivers: budget, schedule, available commercial off-the-shelf (COTS) software, customer standards, user mission or technology uncertainties, etc. The primary process modeling approach to date for avoiding these mismatches has been to try to develop the perfect process model: one which will work well for any combination of process drivers.