What is Analogous Estimating?
Analogous (top-down) estimating prices new work by comparing it to similar past work, adjusted for differences: "the last three store fit-outs averaged $210 per square foot; this one's slightly bigger, call it $220." It's fast and cheap, and it's the least accurate technique — which is fine, as long as everyone knows that.
Its natural home is early in the project, when you need a rough order of magnitude and detail doesn't exist yet. The exam ranking to remember, least to most accurate: analogous → parametric → three-point → bottom-up.
Worked example
Asked for a budget number in the first steering meeting, the PM says: "Our last two mobile apps of this size cost $350K and $410K over 5–6 months. Assume $400K and six months, ±40%, until we've done real planning." Honest speed — with the uncertainty stated out loud.