Which factor should be documented and periodically reviewed during project planning?

Documenting assumptions during project planning is crucial because assumptions are the foundation upon which many project decisions are built. These are conditions that are accepted as true for the purpose of planning, but they may not be verified or certain.

Reviewing these assumptions periodically is essential because the reality of the project may change over time. If an assumption turns out to be incorrect, it can lead to significant project risks or failures. By consistently revisiting these assumptions, the project team can adjust their plans and strategies to reflect any changes in the project's environment or context, ensuring that the project remains feasible and aligned with its objectives.

While costs, revenue forecasts, and employee assignments are important factors to consider, they typically do not carry the same level of uncertainty inherent to assumptions and their potential impact on project success. Therefore, focusing on the assumptions allows a project team to navigate uncertainty more effectively and make informed decisions throughout the project lifecycle.