The incremental method is in many ways a superset of the Waterfall Model. Projects following the Incremental approach subdivide the requirements specifications into smaller buildable projects (or modules).
Within each of those smaller requirements subsets, a development life cycle exists which includes the phases described in the Waterfall approach. The goal is to produce a working portion of the application demonstrating real functionality early in the broader SDLC. Each subsequent “increment” adds additional functionality to the application. Successive rounds continue until the final product is produced. Several of the
development models are variants of the Incremental model including Spiral and RAD.