What is iterative and incremental development?
IN AN ITERATIVE and incremental life cycle (Figure 1-3), development proceeds as a series of iterations that evolve into the final system. Each iteration consists of one or more of the following process components: business modeling, requirements, analysis, design, implementation, test, and deployment. The developers do not assume that all requirements are known at the beginning of the life cycle; indeed change is anticipated throughout all phases.
This type of life cycle is a risk-mitigating process. Technical risks are assessed and prioritized early in the life cycle and are revised during the development of each iteration. Risks are attached to each iteration so that successful completion of the iteration alleviates the risks attached to it. The releases are scheduled to ensure that the highest risks are tackled first. Building the system in this fashion exposes and mitigates the risks of the system early in the life cycle. The result of this life cycle approach is less risk coupled with minimal investment.4
Figure 1-3 Iterative and Incremental Development