Andrew Crossley

    How do you validate a startup idea?

    SHORT ANSWER

    Validate a startup idea by testing willingness to pay, not enthusiasm. Run ten to fifteen interviews about what people did last time they faced the problem, then ask for a commitment — a deposit, a paid pilot, a signed letter of intent. Set your pass thresholds before you start. Two weeks of this routinely prevents six months of building the wrong thing.

    Answered by Andrew Crossley, Fractional Chief Product Officer · Updated 2026-08-01

    Why it matters

    People are polite. Interest costs nothing, so it tells you nothing; commitment costs something, so it tells you almost everything.

    Validation also defines the segment, which is what makes every later prioritisation decision easier.

    How it works in practice

    1. 1

      Write the falsifiable assumption

      'Operations managers at 20-100 person logistics firms will pay £200/month to remove manual reconciliation.' Specific enough to be wrong.

    2. 2

      Set the thresholds in advance

      e.g. at least six of fifteen describe the problem unprompted, and at least three commit. Deciding thresholds afterwards guarantees a pass.

    3. 3

      Interview about the past

      What did you do last time? What did it cost? What did you try? Never ask whether they would use a hypothetical product.

    4. 4

      Ask for a commitment

      Deposit, pilot fee, letter of intent, or a scheduled onboarding slot. Money is best.

    5. 5

      Run a smoke test in parallel

      A landing page with a real price and a real call to action, driven by direct outreach to the exact segment.

    6. 6

      Decide against the thresholds

      Pass, iterate the problem statement, or drop it. Write the decision down.

    Common mistakes

    • Pitching during interviews, which converts research into a sales call.
    • Interviewing friends and peers rather than the target segment.
    • Counting waitlist signups as validation — free interest predicts very little.
    • Moving the goalposts when the evidence is weak.

    FROM EXPERIENCE

    What a commitment signal looks like

    The clearest validation I have seen in B2B is a small paid pilot agreed before anything exists: a defined scope, a start date and an invoice. It converts a conversation into a business decision on the customer's side.

    In consumer, the equivalent is a pre-order or a deposit. Everything softer than that — sign-ups, likes, 'definitely interested' — is noise.

    Frequently asked

    How many interviews are enough?

    Ten to fifteen in one segment. Patterns repeat quickly; if they do not, your segment is too broad.

    Can I validate without building anything?

    Yes, and you should try. A clear offer, a price and a commitment ask need no product.

    What if the answer is no?

    That is a successful validation. You bought the information for two weeks instead of six months.

    IN SHORT

    • Test willingness to pay, not interest.
    • Behavioural interviews plus a commitment signal, with thresholds set in advance.
    • Two weeks of validation regularly saves half a year of building.

    Idea to MVP in six weeks

    A validated, instrumented first product in front of real users.

    Idea to MVP in six weeks

    THE FRAMEWORK

    The Crossley Method: idea to first revenue in seven stages

    See the full method
    1. STAGE 1DiscoverWeek 1
    2. STAGE 2ValidateWeek 2
    3. STAGE 3PrototypeWeek 3
    4. STAGE 4Build MVPWeeks 3-4
    5. STAGE 5LaunchWeek 5
    6. STAGE 6First RevenueWeek 6
    7. STAGE 7ScaleOngoing

    MORE ANSWERS

    Startup founders

    How do I start a SaaS company?

    Start a SaaS company by choosing a narrow, expensive, recurring problem for a specific group you can reach, validating that they will pay before you build, then shipping the smallest product that solves it end to end. Get to first paid customer before hiring, raising or automating anything. Distribution — how you reach that group repeatedly — matters more than the software.

    How do I find a technical co-founder?

    Technical co-founders come from people who already know you — former colleagues, communities you contribute to, and open-source or startup circles — far more often than from matching platforms. What makes them say yes is evidence: a validated problem, early customers, and a prototype you built yourself. In 2026, many founders should first ask whether they need a co-founder or a contractor plus AI tooling.

    What mistakes do first-time founders make?

    First-time founders consistently build before validating, scope too wide, hire too early, price too low, chase funding instead of revenue, and measure activity instead of outcomes. Each individually is survivable. Combined, they burn a runway cycle before anyone learns whether the core idea works. The counter-move is uncomfortable focus: one segment, one problem, one metric, one channel.

    What framework should founders use?

    Founders need one sequence, not a shelf of frameworks. A workable one: discover the problem, validate willingness to pay, prototype the flow, build the MVP, launch narrow, get first revenue, then scale what works. Borrow specific tools where they help — jobs-to-be-done for framing, opportunity solution trees for discovery — but a framework that produces artefacts instead of decisions is overhead.