For planning purposes, assumptions are:

Assumptions are factors taken as true to allow planning to proceed, not directly used to resolve constraints, although they might influence how constraints are managed.

In project management, an assumption is a factor in the planning process that is considered to be true, real, or certain, without proof or demonstration. Project teams make assumptions when they do not have complete information, allowing them to proceed with planning based on what they believe will happen. These assumptions are documented and monitored, as their invalidation can impact the project.

Assumptions are used throughout the entire project lifecycle, not just during the initiation phase, as new assumptions can emerge or existing ones need to be re-evaluated during planning, execution, and monitoring.

Assumptions are not necessarily "resolved" as the project is elaborated; rather, they are validated, monitored, and updated as more information becomes available, and if proven false, they lead to replanning.