A collaborative spiral software process model based on Theory W

A primary difficulty in applying the spiral model has been the lack of explicit process guidance in determining the prospective system's objectives, constraints, and alternatives that get elaborated in each cycle. This paper presents an extension of the spiral model, called the Next Generation Process Model (NGPM), which uses the Theory W(win-win) approach (Boehm-Ross, 1989) to converge on a system's next-level objectives, constraints, and alternatives. The refined Spiral Model explicitly addresses the need for concurrent analysis, risk resolution definition, and elaboration of both the software product and the software process in a collaborative manner. This paper also describes some of the key elements of the support system developed based on the model and refined through experiments with it. It reports on experiences in applying NGPM to a large Department of Defense program.<>