The beneficial result that I can hope for as a consequence of this work is that more attention will be paid to the precise statement of the alternatives involved in the questions being asked.
– Theory of Probability, H. Jeffery, Cambridge University Press, 1939, p. vi.
Since all project work operates in the presence of uncertainty, reducible and irreducible, estimates are always needed when the value at risk exceeds the level tolerable by management to make a decision without knowing the outcome of that decision.