Role:  Integrator

Implementers deliver their tested components into an integration workspace, whereas integrators combine them to produce a build. An integrator is also responsible for planning the integration, which takes place at the subsystem and system levels, with each having a separate integration workspace. Tested components are delivered from an implementer's private development workspace into a subsystem integration workspace, whereas integrated implementation subsystems are delivered from the subsystem integration workspace into the system integration workspace. 

Staffing

It may sometimes be appropriate for an individual acting as an integrator to also act as a Role: Tester. For example, if the project is small or the integration is at the subsystem level, it may be an effective use of resources to have the integrator and tester be the same team member. Indeed, for subsystem-level integration and test, a single individual might play the role of implementer, integrator, and tester. At the system level, however, we recommend that integration and testing are performed by an independent team.