Project refers to all actions to be taken in order to meet a defined need within fixed deadlines. Thus, because a project is a temporary action with a beginning and an end, mobilizing identified resources (human and material) during its execution, it also has a cost, and must therefore have resources budgeted and a balance sheet independent of that of the company. "Deliverables" refer to the expected results of the project.

The difficulty of project management lies to a great extent in the large number of persons involved. In fact, in contrast to personal or small-scale internal projects for which the need and the response to the need can be supplied by the same person, or by a limited number of people, in a project in the professional sense, the expression of the need and the satisfaction of this need are generally the responsibilities of different people.

Thus, it is necessary to make sure - for the entire duration of the project - that the product being created clearly meets the "client's" expectations. As opposed to the traditional commercial model ("seller/buyer") where a customer buys a ready-made product in order to meet a need, the project seeks to create an original product meeting a specific need that must be expressed precisely. This expression of needs is even more difficult because the project generally has no precedent within the company, given its novelty. Conversely, it is generally difficult to abstract existing solutions and concentrate solely on the needs in functional terms.