The Triple Constraint in Project Management

Abstract

When managing a project several aspects constraints the project. These constraints are interdependent and the three key constraints form what has traditionally been known as the The Triple Constraint or The Iron Triangle. Some claim time, scope and cost (TCS) to be the key constraints others claim it is time, cost and quality (TCQ) . It is either way the project managers job to balance between the constraints to obtain trade-offs within a reasonable limit during the project's life cycle to obtain a successful project. The model implies that the project's successful completion is affected by the trade-offs performed and it is the project managers job to know how the constraints interrelate. The model however does not determine success . The model has been widely used since the 1950s and the application and limitations have been discussed extensively . Atkinson is one of the critics who claims the model is insufficient for determine the project success, because success rely on several additional factors and not only the three constraints . Others are more positive, but in general it seem that many would like to modify the model to improve the interpretation . Predominantly there seems to be a disagreement about whether scope or cost is the third constraint in the triangle. The aim of this paper is to explain the concept of the triplet constrain and it's application and limitations in project management and to reflect on the different perspectives.