Feedback Loops are a foundational systems thinking concept describing how a system's output circles back to influence its own input, creating either self-reinforcing (positive) or self-correcting (negative) dynamics. Understanding whether a system's loops are amplifying or stabilizing — and where the delays are — is the essential first step in diagnosing why complex systems behave the way they do.
Leverage Points are the places in a system where a small shift can produce large, lasting changes in system behavior. Donella Meadows identified 12 leverage points in order of increasing power — from adjusting numbers (low leverage) to changing the paradigm underlying the system (highest leverage). Most interventions target low-leverage points; the highest-impact interventions are often counterintuitive and politically uncomfortable.
Stocks and Flows is a foundational systems thinking framework for understanding how systems accumulate and change over time. Stocks are quantities that accumulate — inventory, money, population, knowledge, goodwill. Flows are the rates of change — in-flows increase stocks, out-flows decrease them. Almost all system behavior can be understood by mapping what stocks exist in a system and what flows control their accumulation.