Terms of reference (TOR) define the purpose and structures of a project, committee, meeting, negotiation, or any similar collection of people who have agreed to work together to accomplish a shared goal.

Terms of reference show how the object in question will be defined, developed, and verified. They should also provide a documented basis for making future decisions and for confirming or developing a common understanding of the scope among stakeholders. In order to meet these criteria, success factors/risks and constraints are fundamental. They define the:

• vision, objectives, scope and deliverables (i.e. what has to be achieved)
• stakeholders, roles and responsibilities (i.e. who will take part in it)
• resource, financial and quality plans (i.e. how it will be achieved)
• work breakdown structure and schedule (i.e. when it will be achieved)

TORs should include:

• success factors, risks and constraints.

Although the terms of reference of a project are sometimes referred to as the project charter, there are significant differences between the two. This article describes a TOR containing detailed definitions, while a project charter has high-level requirements, assumptions, constraints and descriptions as well as a budget summary without detail, and a milestone-only schedule.