Every project has to manage four basic constraints; scope, schedule, budget and quality. The success of a project depends on the skills and knowledge of a project manager to take into consideration these constraints and develop the plans and processes to keep them in balance. It is not enough for a project to meet the budget targets or to show to the donor that all activities have been completed on time. Development projects need to balance all four constraints if they want to realize the full benefits of a project.
Classical project management usually considers three constrains on a project: scope, time and costs (known as the project triangle), we believe that it is important to place under this category the constraint of quality. For development projects it is not enough to deliver a project according to the scope, on time and under budget; but the project must meet the needs and expectation of the beneficiaries who are the ultimate judges of the project quality.
Managing these constrains requires careful analysis and an agreement on the priorities for the organizations, the donor and the final beneficiaries. Depending on those factors a project may place more importance to the budget and quality than to the schedule or scope; these types of decisions, early in the project, have a fundamental impact on all the project plans that will need to be designed to ensure that the project is able to manage the four constraints. Failure to do that may result in the use of resources on areas that do not contribute to the ultimate success of the project.
The definition of project management implies that projects have specific limits in scope, schedule, budget and quality. Understanding the combination of elements will allow make better choices when the project needs to make tradeoffs. The use of a triangle helps understand these relationships, adjusting any one of these sides, the other two are affected. For example, a change in the project plan to shorten the schedule might result in an increase in costs or require a decrease in scope.