Systems Thinking (Stocks and Flows)
by Will Larson • CTO at Carta at Carta
Former engineering leader at Stripe, Uber, and Calm. Author of the influential books 'An Elegant Puzzle', 'Staff Engineer', and the upcoming 'The Engineering Executive's Primer'. He writes the popular engineering leadership blog lethain.com.
🎙️ Episode Context
Will Larson discusses the shifting landscape of engineering leadership post-ZIRP, emphasizing the need to stop coddling engineers and start giving them business accountability. He breaks down frameworks for engineering strategy, systems thinking, and defining actionable company values, while sharing personal insights on writing and handling failure.
Problem It Solves
Helps debug complex organizational processes (like hiring or incident management) where simple cause-and-effect logic fails.
Framework Overview
Instead of viewing problems in isolation, model them as 'Stocks' (accumulations) and 'Flows' (movement between stocks). Identify where reality deviates from your model to find the root cause.
🧠 Framework Structure
Model the System: Map out the inputs,...
Reality Check: Compare your model's p...
Reality is Right: If the model confli...
Don't Over-Measure: Avoid the trap of...
When to Use
When a process isn't yielding results (e.g., lots of interviews but no hires) and intuition is failing.
Common Mistakes
Thinking reality is 'wrong' because it doesn't fit your elegant model, or getting so caught up in analysis that you never improve the system.
Real World Example
Larson used this to debug a hiring pipeline. By modeling stocks/flows, he realized the issue wasn't candidate volume, but hiring managers' inability to make decisions (high offer stage stock, low conversion flow).
Reality is always right. Your model is always wrong if it's in conflict with reality.
— Will Larson