Any part of the triangle may change during the project – whether as a result of constraints / changes in the project itself or those that affect it from the outside. For example, it is quite common for there to be changes in the project’s resources or schedule due to different constraints. The project budget may also change as a result of constraints. But particularly interesting is actually the scope because it has a natural tendency to grow – regardless of external constraints, simply by the very nature of a project. There are two main reasons for the increase in the project scope:
- Legitimate reasons stemming from the low level of certainty that characterizes projects;
- Non-material reasons related to partial or defective planning.
The role of the project manager is to ensure the best possible planning under uncertainty, and to prepare well for the inherent uncertainty of a project.