Your North Star Metric Is Wrong (and It's Killing Your Retention) ft. Mark Roberge (Stage 2 Capital)

Most founders treat product-market fit like a feeling. Mark Roberge thinks that's as absurd as calling profit a feeling.

The founding CRO of HubSpot, Harvard Business School lecturer, and Stage 2 Capital co-founder joins Josh to break down his new book, The Science of Scaling. The argument at the center of it - the decision of when and how fast to scale shouldn't be a gut call. It should be gated on retention.

Mark shares the leading indicator of retention (the one metric that predicts churn in a customer's first month), the 5-50-500 playbook a Microsoft leader used to launch new products, why Drift's founder flew across the country to onboard $50/month customers, and what "AI-native sales team" should actually mean in 2026 (with numbers attached).

If you work in Customer Success, this episode makes the case that you own the most strategic metric in the company. All proceeds from Mark's book go to McLean Hospital for mental health care.

--- Want the playbook, not just the conversation? Subscribe for deep-dive, actionable breakdowns from every episode at unchurned.substack.com.

---

What You'll Learn - Why we scale haphazardly, not scientifically - A quantitative definition of product-market fit - How to design a leading indicator of retention - Real LIR examples from Slack, Harvey, Facebook, and Gainsight - The three maturity levels of an LIR - How a Microsoft leader used the 5-50-500 rep model to de-risk new product launches - How to pick your threshold based on the blitzscale risk in your category - Why product-market fit and go-to-market fit must be sequenced, not pursued at once - How to know when to move past founder-led sales - How to bring unit economics into board meetings - Why blitzscaling fails more companies than it saves (and why VCs push it anyway) - The two metrics that define an AI-native sales team in 2026 - Mark's four phases of the AI revolution in go-to-market

--- Timestamps 0:00 - Preview & Intro 1:30 - Meet Mark Roberge 3:07 - The Science of Scaling (All book proceeds go to McLean Hospital) 7:30 - We scale haphazardly, not scientifically 9:06 - Microsoft's 5-50-500 playbook 13:19 - Is product-market fit a feeling? 15:48 - The leading indicator of retention, explained 17:30 - Time to value vs. recurring value 19:42 - Designing your own LIR 24:04 - Why go-to-market fit comes after PMF 26:06 - Pitching this framework to VCs 28:15 - How to know when you have go-to-market fit 31:15 - Bringing the science to larger companies 33:00 - When to move beyond founder-led sales 35:51 - AI and the four phases of the GTM revolution 37:20 - What "AI-native sales team" means in 2026

--- Josh is writing a book on building customer relationships. Follow his journey and insights at www.joshschachter.com

--- Where to Find the Guest Mark Roberge: https://www.linkedin.com/in/markroberge/ The Science of Scaling: https://a.co/d/0boDpDUc Stage 2 Capital: https://www.stage2.capital/

--- Where to Find the Host: Josh's LinkedIn: https://www.linkedin.com/in/jschachter/ Unchurned Substack: https://unchurned.substack.com/