All projects have a minimum of 14 roles:
- Sponsor/Governing Body/Steering Committee
- Scope Manager (Change Mgr/Config. Mgr)
- Project Controls (Financials, Invoicing, EV, etc.)
- HR Manager
- Quality Manager
- Communications Manager
- Procurement Manager
- Risk Manager
- Developer/Worker (I know IT stole the word, I am taking it back :))
- Subject Matter Expert
- Project Admin
- Stakeholder (in most cases)
The size of the project is irrelevant. Even if the project requires only two human beings staffed full-time, each of these roles will need to be filled by one of these two people who will spend some of their 40 to 50 hour work week devoted to fulfilling the tasks within these roles.
Response to comments: I like the additional role of stakeholder but I am not sure they are a required role for every project. For example, a small home project would not necessarily have stakeholders that must remain in some way informed. I added anyway because I think in majority of the cases it is true.