How to debug a team that isn’t working: the Waterline Model

2026-03-03 · Source: Lenny's Newsletter · Field: Business & Management — Corporate Strategy & Leadership, Entrepreneurship & Start-ups, Operations & Process Management · Depth: Intermediate, long

Summary

Molly Graham introduces the "Waterline Model," a management framework designed to diagnose and resolve team challenges by systematically identifying their root causes. Drawing from two decades of experience at companies like Google and Facebook, Graham argues against immediately blaming individuals for performance issues, suggesting that structural problems are often the real culprits. The model proposes four levels for diagnosis: structure, dynamics, interpersonal, and individual, to be investigated in that specific order. It emphasizes starting with "snorkeling" (examining shared systems like goals and roles) before "scuba diving" into individual personalities. This approach helps leaders avoid misdiagnosing problems, cycling through personnel unnecessarily, and wasting resources on ineffective solutions, ultimately improving team performance by addressing the correct underlying issues.

Key takeaway

For product managers or team leads experiencing persistent underperformance, adopt the Waterline Model to systematically diagnose issues. Instead of immediately questioning individual capabilities, first evaluate if unclear goals, undefined roles, or inconsistent decision-making dynamics are creating the problem. This approach ensures you address the root cause, preventing unnecessary team turnover and fostering a more effective, predictable work environment by fixing the system, not just the symptoms.

Key insights

The Waterline Model diagnoses team problems by systematically addressing structural and dynamic issues before individual ones.

Principles

• Blaming people for structural problems is a major leadership trap.
• Snorkel before you scuba: start with shared systems, then go deeper.
• Teams adapt rationally to the systems and signals leaders create.

Method

Diagnose team underperformance by sequentially examining four levels: structure (goals, roles), dynamics (team behavior, decision-making), interpersonal (relationships), and individual (skill gaps, personal issues). Address higher-level issues first.

In practice

• Reclarify team mandate, goals, and individual roles to fix structural issues.
• Leaders must be consistent in decision-making to improve team dynamics.
• Address interpersonal conflict directly after ruling out structural causes.

Topics

• Waterline Model
• Team Problem Diagnosis
• Organizational Structure
• Team Dynamics
• Leadership Frameworks

Best for: Executive, Entrepreneur, Product Manager

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Editorial summary, takeaway, and curation by AIssential. Original article published by Lenny's Newsletter.