Why we picked it Sean Ellis coined the North Star idea, so this is the walkthrough straight from the person who popularized it, in plain founder-facing language rather than theory. The full interview is long, but there is a dedicated Picking a North Star metric segment (around the 1:19 mark) worth jumping to first. His rule of thumb, that the metric should reflect core value, be actionable, not a ratio, and able to scale, is the honest gut-check for whether your free-plus-paid number is the right one.
The original growth hacker reveals his secrets | Sean Ellis (author of "Hacking Growth")
On Lenny's Podcast (YouTube) by Sean Ellis, interviewed by Lenny Rachitsky About 95 minutes (North Star segment near 1:19:21)
- The North Star should capture the core value your product delivers to users, not revenue itself, though it should correlate with revenue growth.
- Ellis warns against a ratio as your North Star: pick a number that can grow, which matters when free and paid tempt you toward conversion-rate framing.
- Skip to the Picking a North Star metric segment near 1:19:21 if you only want the metric-selection part rather than the full growth conversation.