The purpose of the plan purchases and acquisitions process is to identify which project needs can best be met by purchasing and acquiring products, services, or results outside the project organization. This process involves consideration of whether, how, what, how much, and when to acquire. When the project obtains products, services, and results required for project performance from outside the performing organization, the processes from plan purchases and acquisitions through contract closure are performed for each item to be purchased or acquired.

The plan purchases and acquisitions process encompasses the consideration of potential vendors, particularly if the buyer likes to exercise some degree of influence or control over contracting decisions. Emphasis should also be given to who is responsible for obtaining or holding any relevant permits and professional licenses that may be required by legislation, regulation, or organizational policy in executing the project.

The project schedule is a key input to create plan purchases and acquisitions process. Decisions made in developing the procurement management plan can also influence the project schedule and are integrated with schedule development, activity resource estimating and make or buy decisions.