Figure 8: MSDL of the Spiral Model Level 1
Differences in the need for human involvement: As in the
system objectives phase human involvement is essential for their
definition, there is no way to differentiating the human
involvement in this phase.
Differences in the development procedure: The order in both
models are quite similar, actually when they refer to the
development model many stages do not exist before the phase of
definition of objectives. However, the Spiral Model stands out as
having some additional components that differentiate it in the
quality of the stage: Risks associated to Cost and Alternative
Solutions. These components are important and fundamental in
the definition of objectives and they should be pointed out.