Our study defined collaboration as "a reciprocal and voluntary agreement between two or more distinct public sector agencies, or between public and private or nonprofit entities, to deliver government services."

These arrangements often rest on a formal agreement specifying the purpose of the collaboration, and the allocation of associated responsibilities, risks, benefits, and resources. Often these agreements take the form of time- limited contracts. In general, each collaboration project involved:

• a minimum of two organizations,
• a formal agreement about roles and responsibilities,
• a common objective, activity, or project aimed at the delivery of a public service, and
• the sharing or allocation of risks, benefits, and resources - both tangible and intangible.

Many of the projects involved all three sectors, but one of the following main types dominated each arrangement.

Public-public collaborations. This category includes both horizontal agreements between two agencies or departments at the same level of government, and vertical agreements or intergovernmental alliances among federal, state, and local levels.

Public-private collaborations. Public-private partnerships go beyond traditional contracting and outsourcing to include a more equal sharing of the resources, risks and benefits associated with project operations. In these cases, government hands over part of its management responsibilities while retaining enough control to ensure the protection of the public interest.

Public-nonprofit collaborations. Traditionally, the relationship between nonprofit organizations and government has been characterized by fee-for-service contracts. Today, we are beginning to see joint development of service programs in which the public and nonprofit participants share responsibility for program design, performance, and evaluation.