Start with the job being done and the size of the reachable market, and treat any segment description as a hypothesis. The tools here that carry a Folklore mark are the ones most likely to produce a confident answer that is wrong.
8 tools across 3 of the 9 questions
A method that defines demand by the progress a customer is trying to make, rather than by product category or customer profile.
Breaks when In low-involvement, habitual purchases it degenerates into inventing a job that was never there. Not every purchase has a purpose behind it.
Understand the marketDividing a market into groups expected to behave differently, then choosing which of those groups to serve.
Breaks when It breaks as a description of who buys. Competing brands within a category are repeatedly measured as having near-identical buyer profiles: the segments differ in size, not in kind. A segmentation that assigns each brand its own distinct demographic or attitudinal buyer is describing a market that measurement does not find. It survives as a targeting and media convenience, not as a theory of demand.
Understand the marketA composite fictional buyer — name, age, role, frustrations — built so a team has a concrete person to design and write for.
Breaks when It breaks the moment the fiction is treated as evidence. Personas are typically built from a handful of interviews and then used to exclude — this campaign is not for her, that channel is not where he is. Because competing brands largely share the same buyers, a persona used to exclude is excluding people who already buy from you. The failure is silent: nobody audits the customers a persona quietly wrote off.
Understand the marketA three-layer market sizing convention: the total market, the portion a given business model can serve, and the share it could realistically win.
Breaks when Produces no decision. The number is almost always reverse-engineered from the desired conclusion, and it never identifies which assumption is the fragile one.
Understand the marketThe claim that a discontinuity in buying logic separates early adopters from the early majority, crossed by dominating one narrow beachhead first.
Breaks when No empirical support for the chasm itself. Outside B2B technology the mechanism has little to stand on — the focus advice is good, the theory under it is not.
Understand the marketA survey rule of thumb: ask users how they would feel if they could no longer use the product, and treat 40% answering “very disappointed” as the threshold for fit.
Breaks when The 40% threshold has no published derivation — it is a remembered benchmark from a small set of startups, not an estimate with an interval around it. Worse, the survey only reaches people still using the product, so it measures the enthusiasm of survivors and is structurally silent on everyone who already left. A product with a small, devoted, unscalable audience passes it comfortably; that is the exact failure mode it is meant to catch.
Decide what to offerThe heuristic that the greatest advantage in any business is an audience already desperate to buy, so demand should be chosen before the product.
Breaks when Visible demand is the most contested resource there is. A crowd everyone can see is a crowd everyone is already selling to, so the heuristic routes founders straight at the categories with the highest acquisition costs and the most entrenched incumbents. It also carries no test — nothing in it distinguishes a starving crowd from a well-fed one until the money has been spent finding out.
Understand the marketA five-step ladder describing how much a prospect already knows — unaware, problem aware, solution aware, product aware, most aware — used to decide where a message has to start.
Breaks when There is no measurement attached to it. Nothing tells you which stage a visitor occupies, so the stage is assigned afterwards from what the copy did — a page that failed gets re-diagnosed as aimed at the wrong stage, and the ladder is never wrong. It also assumes one reader per page, and paid traffic delivers all five stages to the same URL at once.
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