Team process: rolls S. Ingraham

leader/coordinator:
responsibility for general direction (vision), project design, managing the decision making process, motivation, etc.
manager/coordinator
responsibility for scheduling and allocation of resources, managing work flow, managing the setting of goals and deadlines, etc.
creative resource/creative specialist (one or more)
responsible for conceptualization and creative implementation of the project, creative use of resources, generating unique solutions to problems as they arise, etc.
monitor/recorder (documentation specialist)
responsible for tracking the progress of the project, making a record of the work as it happens, keeping accurate records, etc.
research specialist/investigator (one or more)
responsible for finding the information and resources needed to complete the project
communications specialist/reporter
responsible for formulating the presentation of the project, and any communications needed to complete the project
facilitator/human resource specialist
responsible for encouraging the contribution of each team member, resolving (or managing) team conflicts, encouraging team communication, etc.

A single person may combine more than one role: the leader may also be the manager or the facilitator, the communications specialist may also be a creative resource for the project as a whole, etc.
Each team member fills at least part of the functions of each role, part of the time, but the designated role filler assumes responsibility for all the functions of the role.
All roles are equally valued.