North Star MetricvsProduct-Market Fit (PMF)

Your North Star Metric is the single number that best captures the core value your product delivers to customers. Airbnb's is 'Nights Booked.' Spotify's is 'Time Spent Listening.' When this metric goes up, everything else follows — revenue, retention, referrals. It aligns the entire company around one measurable goal.

Product-Market Fit is the degree to which your product satisfies a strong market demand. When you have PMF, customers are actively pulling your product from you rather than you pushing it onto them. Marc Andreessen defined it as 'being in a good market with a product that can satisfy that market.' The Sean Ellis test quantifies it: if 40%+ of users say they'd be 'very disappointed' without your product, you have PMF. Before PMF, nothing else matters — marketing spend is wasted, hiring is premature, and features are guesses. After PMF, everything gets easier: organic growth appears, retention improves, and word-of-mouth starts compounding.

The biggest mistake is choosing a vanity metric as your North Star. 'Total Users' sounds impressive but ignores whether those users are active or getting value. Zynga had hundreds of millions of registered users but collapsed because their North Star should have been 'Daily Active Players,' not sign-ups.

Founders declare PMF too early based on vanity metrics — sign-ups, press coverage, 'exciting conversations' with potential customers. True PMF means users would be genuinely disappointed if your product disappeared. The second trap: assuming PMF is binary and permanent. PMF exists on a spectrum and can erode as markets shift (Blackberry had PMF until iPhone changed the market). Also: PMF for one segment doesn't mean PMF for another — you might have PMF with startups but not enterprises.

Pick a metric that reflects VALUE DELIVERY, not revenue directly. Test it with this framework: (1) Does it measure the value users get? (2) Does it predict long-term revenue? (3) Can every team influence it? If yes to all three, you have your North Star. Rally the entire team around this single metric.

Run the Sean Ellis survey: ask existing users 'How would you feel if you could no longer use [product]?' with options: Very Disappointed, Somewhat Disappointed, Not Disappointed. If 40%+ say 'Very Disappointed,' you likely have PMF. If not, interview the disappointed users to learn what they love, and double down on that specific value. Track the PMF score quarterly — it should improve as you refine the product.