Assumptions made during the planning stage should be_____________.

Assumptions are necessary placeholders for unknown information during the initial planning stages. They are foundational to creating the initial project plan and schedule. However, a core principle of progressive elaboration and effective project management is to actively seek out factual information to replace these assumptions as the project moves forward. This reduces uncertainty and risk, leading to a more accurate and reliable plan. Leaving assumptions unverified increases the risk of project failure.

A. While assumptions are a source of risk, the primary goal is to eliminate them with facts, not simply to shift the risk.
C. Experience is a valid basis for assumptions, but stating it as the sole basis is too restrictive; other sources are also used.
D. Assumptions must be documented, but specifying an "internal memo" is arbitrary; they are typically recorded in a Basis of Schedule or project plan.

1. AACE International. (2019). Recommended Practice No. 10S-90: Cost Engineering Terminology. Document ID 15834, p. 13. (Defines "Assumption" as a statement taken as true in the absence of proof for the purpose of planning).

2. AACE International. (2015). Skills & Knowledge of Cost Engineering (6th ed.). Section 2.2.2, p. 2.2.5. (Discusses the planning process, which involves making assumptions that are refined as more information becomes available).