, when we
approach big, expensive, and intricate project proposals, we take route of spiral model as our
development methodology. Through this model, we combine designing and programming elements in
all stages. Therefore, designing and prototyping processes are visible on each stages of project
lifecycle and remain up to end.
Thus, we combine advantage of top-down as well as
bottom-up concepts through this model or say system development method.
In this method, we divide development process in four major stages like planning, risk analysis,
programming, and customer evaluation.