---
id: "prereq-lean-startup"
type: "prereq"
source_timestamps: ["§ They Mistakenly Believe They've Reached Product-Market Fit"]
tags: ["product-development"]
related: ["claim-false-pmf"]
reason: "Required to understand why building products in isolation is considered a fundamental error in modern tech entrepreneurship."
sources: ["commercial"]
sourceVaultSlug: "hbr-seg-commercial"
originDay: 5
articleStem: "hbr-ext-21-founders-new-sales-playbook"
sourceUrl: "https://hbr.org/2026/06/startup-founders-need-a-new-sales-playbook"
sourceTitle: "Startup Founders Need a New Sales Playbook"
---
# Lean Startup Methodology

**Prerequisite knowledge:** The **Lean Startup** methodology (Eric Ries) is referenced as the antidote to building products in isolation.

To fully grasp why perfecting a product before customer exposure is a *"classic error,"* a downstream agent must understand:
- The **Build–Measure–Learn** feedback loop
- The **Minimum Viable Product (MVP)**
- **Validated learning** — treating PMF as evidence of a *sustainable, paid, repeatable* business model, not just enthusiastic free usage

**Why it matters here:** This background is what makes [[claim-false-pmf]] legible — free pilots produce vanity usage, not validated learning.