The Only 3 Metrics That Matter for Early-Stage PMF
Vanity metrics will kill your startup. Forget 'Total Signups'. Here are the three indicators that actually prove Product-Market Fit.
Startups die because they confuse "Growth" with "Fit." They buy ads, get signups, and celebrate. But if those users leave next month, you don't have a business; you have a leaky bucket.
Before you scale, you need Product-Market Fit (PMF). Here are the only 3 metrics that confirm it.
1. The "Sean Ellis" Test (The 40% Rule)
Ask your users: "How would you feel if you could no longer use [Product]?"
- A) Very disappointed
- B) Somewhat disappointed
- C) Not disappointed
The Benchmark: If >40% say "Very disappointed," you have PMF. If it's 20%, do not scale marketing. Go back to product discovery. Fix the core value proposition.
2. Cohort Retention (The Flattening Curve)
Look at your retention cohorts.
- Month 1: 100%
- Month 2: 60%
- Month 3: 40%
- Month 12: 40%
Does the line flatten? If it goes to 0%, you are dead. If it flattens at a non-zero number (e.g., 40%), it means you have found a core group of users who stick around forever. That is your foundation.
3. Organic Growth (The Word of Mouth)
Are people inviting others without you paying them? PMF feels like the market is pulling the product out of you. If every signup is a tooth-and-nail fight, you don't have fit.
How to Move the Needle
If your scores are low, don't A/B test button colors. Go deeper. Use Fieldrun to interview the users who said "Somewhat disappointed." ask them: "What is the one thing that would make you 'Very disappointed' to lose us?"
Build that. Then measure again.