Iterative process models are process models that repeat stages of the process.

The advantage of iterative processes is the ability to loop and revisit previous phases (and their activities) as part of the process. Each “loop back” is an iteration, hence the name “iterative process.” Iterations allow for client feedback to be incorporated within the process as being the norm, not the exception. Iterative process models are readily amenable to Agile practices, yet they also embody sequential portions reminiscent of linear process models.

Example

Spiral model