i used to panic at prompts with fuzzy language — “addressable market” this and “users” that. what changed: i started translating vague terms into measurable drivers (total population, penetration, frequency) and always mapping my assumptions to known anchors. community vets pushed me to always run one top-down sanity check against a macro figure. after that, i tie every segment back to a single observable. when time is short, that keeps my estimate credible. which sanity check do you run first in a timed interview?
top-down first. always. take a known macro (country population, household count, whatever fits) and work backwards. if your bottom-up number outpaces a reasonable top-down by an order of magnitude, you’ve built on fantasy. saying that out loud looks like competence. people who try to justify absurd bottoms-up with micro-assumptions get eaten alive.
also, avoid the ‘addressable market vs serviceable’ sermon unless they ask. most interviewers want clean logic, not taxonomy. segment sensibly, show your math, and if asked add the fancy labels. less fluff, more traceable calc.
i like starting with population then applying a 2-step filter (target demo, adoption rate). it keeps things quick. still nervous about picking rates tho - any simple rule of thumb?
i usually say: i’ll run a top-down check against a known stat. hearing that line calms the room for me. anyone got quick sources to remember?
When a market definition is ambiguous, my advice is to explicitly translate it into operational metrics and document the chain of logic. For example, convert ‘annual addressable market’ into: relevant population × penetration × purchase frequency × average spend. Then pick one public anchor—census data, industry report, or a government statistic—and use it to sanity-check your top-down projection. In coaching sessions I stress speaking your checks aloud; it signals method and invites correction rather than defensiveness.
great approach—translating fuzzy terms into drivers makes you sound way more confident! try a quick 2-minute drill and watch your clarity improve.
a practical routine: define your target metric, map it to 3 drivers, compute the core estimate, then perform two sanity checks: (1) a top-down anchor against a public statistic, (2) a simple ratio check (e.g., market per 1,000 people). if your estimate fails either check by a large margin, adjust assumptions rather than invent new segments. consistent application of this routine helps reproducibility under time pressure.