Typically the most time-consuming and resource-intense phase of the project is the phase in which the project deliverables are created according to the approved deliverable specifications. In other words, to extend our Phase III examples, the software is developed, the building is built, the videotape is produced, and so on.
The specific activities involved in this phase differ dramatically from one industry or application to another. For example, a defense contractor may first need to create a working model to prove the concept works before building the full-blown version of the defense system. Or a software developer will likely create and test small units of code before programming and integrating all software modules. And a video producer would likely create scripts, conduct casting sessions and rehearsals, and produce other interim deliverables prior to engaging in fullblown production activities.