Spiral model

Boehm also identifies a number of misconceptions arising from oversimplifications in the original spiral model diagram.

In a National Research Council report[4] this model was extended to include risks related to human users.

[citation needed] Authentic applications of the spiral model are driven by cycles that always display six characteristics.

[1] Sequentially defining the key artifacts for a project often increases the possibility of developing a system that meets stakeholder "win conditions" (objectives and constraints).

Some "hazardous spiral look-alike" processes violate this invariant by excluding key stakeholders from certain sequential phases or cycles.

However, additional testing time might increase the risk due to a competitor's early market entry.

[citation needed] "Hazardous spiral look-alikes" that violate this invariant include evolutionary processes that ignore risk due to scalability issues, and incremental processes that invest heavily in a technical architecture that must be redesigned or replaced to accommodate future increments of the product.

"Hazardous spiral look-alikes" that violate this invariant include evolutionary and incremental processes that commit significant resources to implementing a solution with a poorly defined architecture.