Work assignments and Work Product responsibilities can be different from Activity to Activity in a development project. Different phases require different staffing profiles, that is, different skills and resources doing different types of work. Therefore, a Process needs to define these profiles in a flexible manner. Whereas Core Method Content defines standard responsibilities and assignments, a Process expressed in breakdown structures needs to be able to refine and redefine these throughout its definition.

Role Descriptors, Composite Roles, as well as Team Profiles provide the data structure necessary to achieve this flexibility and to provide Process users with the capability to define different teams and Role relationships for every Activity (including Activities on any nesting level as well as Iterations or Phases). Hence, in addition to the work breakdown and Work Product breakdown structures, Team Profiles are used to define a third type of breakdown structure: The Team Breakdown Structure. It is created as an Activity specific hierarchy of Team Profiles comprising of Role Descriptors and Composite Roles. These structures can be presented as Org-Charts.