The process begins with some overall project planning.  Then the iterative development cycle (IDC), also referred to as the microcycle, carries the project forward.  The IDC is an incremental approach, in which the system is developed as a series of builds of increasing capability and completeness.  The system (referred to as the “prototype” even though it is fully production quality code) is constructed incrementally, with new builds adding new system-level capabilities to the increasingly complete system.  The advantage of such an incremental approach are well documented in the literature, and include higher quality, lower cost of quality, and even reduced development time.

In the Full Spiral lifecycle, there is a quick initial analysis to identify the set of use cases (and provide a 1-paragraph mission statement), but the use cases are not detailed until later. This means that software work begins before all of the use cases are fully specified. In fact, the use cases are only detailed within the spiral during which they will be realized.