What's the difference between defining a niche and just being too small to matter?
A good niche is small in headcount but deep in pain and willingness to pay, while a bad niche is small because there simply isn't enough there to build on. Test it by math: number of reachable customers times what they'd realistically pay times how often they buy. If a tight niche of a few thousand desperate customers can fund a real business, that's focus, not smallness. If even winning 100 percent of the niche wouldn't sustain you, you're not niching, you're cornering yourself, so treat this as a sizing check rather than a gut feeling.
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This is the canonical argument that you do not need a mass market to build something real, you need a small number of people who deeply want what you make. It is the cleanest way to see that a niche is not the same as being too small, because 1,000 people who buy everything you make is a business, while 100,000 people who half-care is not. Read it as a starting point for reframing what 'big enough' actually means.
This is written by Visible, a platform that sits on the investor side of the table, so it explains bottom-up sizing the way a VC actually reads it. It is direct about why the top-down number collapses under scrutiny and why the bottom-up build wins credibility, which is exactly the tension you are describing. Use it to decide what to lead with, then show top-down only as a sanity check.
Bottom-up sizing (count real customers, multiply by realistic revenue per customer) is more defensible because every assumption is one an investor can poke at and you can answer.
A top-down number pulled from an industry report signals you Googled a big figure rather than understanding who buys, how many exist, and what they pay.
The strongest move is to lead with your bottoms-up number and use top-down as triangulation: if the two diverge a lot, revisit your assumptions before the meeting.
Founders often keep validating because they secretly doubt the idea itself, so a structured way to judge the idea is half the readiness question. YC partner Jared Friedman gives an idea quality score across four criteria (how big, founder/market fit, how sure you are the problem is real, and whether you have a genuine insight) plus the bad filters that make founders quietly reject their best ideas. It is the honest bar to check your idea against before you commit to building. A starting framework, not a scorecard to obsess over.
Rate an idea on four criteria and average them, rather than trusting a gut yes or no.
Great companies usually started from a good enough idea plus strong execution, not a brilliant one, so waiting for the perfect idea is itself a mistake.
Watch for filters (seems hard, boring space, too ambitious, competitors exist) that make you reject strong ideas without realising it.
