“The goal is not to undermine or abandon key assumptions; rather, it is to make them explicit and identify what information or developments would demand rethinking them.”US Government · A Tradecraft Primer: Structured Analytic Techniques for Improving Intelligence Analysis · 2009 · «A Tradecraft Primer: Structured Analytic Techniques for Improving Intelligence Analysis» (Guvernul SUA, martie 2009), secțiunea «Key Assumptions Check», p. 7
The most dangerous premise is the one everybody shares and nobody has written down.
A key assumption is any hypothesis the analyst has accepted as true and on which the assessment rests — often without ever having stated it. The primer proposes four steps: write down the current analytic line where everyone can see it; list all the premises, stated or unstated, that must be true for the line to hold; challenge each one — why it must be true and whether it holds under all conditions; keep only the assumptions that really carry the conclusion, and note the conditions under which they would fail. The primer's example is the 2002 sniper case around Washington, where it was assumed the perpetrator was acting alone. At the CIA in the 1990s, Douglas MacEachin promoted a variant called linchpin analysis: assumptions about the key drivers become linchpins, the premises the argument stands on, and must be spelled out. The method pays at the start of a project, when it costs an hour or two, and again before judgements are finalised. The trap: the list turns into an inventory of platitudes, while the dangerous premise — the one nobody sees because everybody shares it — stays unwritten. The question that brings it out: if this proved wrong, would the conclusion change?
Why it matters Assessments rarely fail because a fact was wrong; they fail because a premise nobody wrote down stopped being true.