About Use Systems Thinking to Find Why a Problem Keeps Coming Back

Past a Threshold a System Switches Behaviour and May not Switch Back Some Behaviour Belongs to the Whole and Cannot Be Found in Any Part A Stock Carries the System's Memory and Cannot Jump to a New Value Judge an Intervention Only After One Full Loop Delay Has Passed A System's Power to Change Its Own Structure Outranks Any Single Change You Make to It Changing a Number Leaves the Loops Intact, Which is Why Parameters Are the Weakest Lever A Stock is an Amount at a Moment and a Flow is a Rate over Time Rules and Incentives Are a Strong Lever Because They Decide Which Loops Can Exist at All Once a Measure Becomes the Goal It Stops Measuring What It Stood for A Reinforcing Loop Produces Exponential Growth or Exponential Collapse Success to the Successful Turns a Small Early Lead into a Permanent Gap A Falling Inflow Keeps Raising a Stock for as Long as It Stays Above the Outflow Growth and Underinvestment Starves Capacity Because Degraded Service Hides the Real Demand A System's Real Purpose is What It Repeatedly Does, Not What It Says It Does A Stock Changes Only Through Its Flows, Never Directly Limits to Growth Ends Every Reinforcing Engine When a Balancing Loop Meets a Constraint A Stock Holds Steady When Inflow Equals Outflow, Not When the Flows Stop Anything in Transit is Itself a Stock, And That Stock is the Delay Eroding Goals Let a Standard Drift Down Whenever the Goal Follows Recent Performance Loop Dominance Shifts Turn Exponential Growth into an S-Curve In the Tragedy of the Commons Each User Gains Privately While the Cost of Depletion is Shared Circular Causality Means Your Cause Comes Back to You as an Effect A Delay Inside a Balancing Loop Causes Overshoot and Oscillation Delivering a Consequence Back to Whoever Causes It Creates a Loop That Was not There Feedback Reacts to a Measured Result While Feed-Forward Acts on a Prediction A Balancing Loop Seeks a Goal and Slows Down as the Gap Closes Where You Draw the System Boundary is a Choice You Make, Not a Fact You Find A System is Elements, Interconnections and a Purpose, and the Interconnections Do Most of the Work A Causal Link Has a Polarity That Says Same Direction or Opposite Direction Under Every Event is a Pattern, Under Every Pattern a Structure, and Under That a Belief A Stock and Flow Diagram Puts Amounts in Boxes and Rates on Valves Shared Mental Models Several Loops Act on One Quantity at Once and Their Sum Sets the Behavior Turn a Prose Story into a Causal Loop Diagram of Named Quantities A System Pushes Back Because Several Actors Are Pulling One Thing Toward Different Goals The Strongest Interventions Usually Make Things Worse Before They Make Them Better Escalation Turns Two Balancing Loops into One Reinforcing Loop of Relative Advantage Information Delays and Material Delays Slow a Loop for Different Reasons Making a Buffer Bigger Steadies a System and Makes It Slower to Change Changing the Length of a Delay Moves Behaviour More than Changing Any Number in the Loop Leverage Points Are Ranked, So Where You Intervene Matters More than How Hard You Push Resilience Comes from Slack and Variety, Which Optimising for Efficiency Removes Count the Negative Links to Tell a Reinforcing Loop from a Balancing One An Archetype is a Loop Structure That Repeats Across Domains with One Signature Behavior Graph A Stock That is Large Compared with Its Flows Absorbs Shocks the Flows Cannot Twice the Cause Does not Give Twice the Effect Shifting the Burden Weakens the Fundamental Solution Every Time the Symptomatic One is Used Structure is Held in Place by What People Believe Must Be True Each Actor Behaves Sensibly on the Information Their Position Lets Them See A Stock Turns Around Exactly Where Its Net Flow Crosses Zero Before You Act, Trace Every Loop the Change Touches and Name the One That Will Push Back Rule of 70 Calculation Method for Doubling Time Feedback Loop Matching a Story to an Archetype Starts from the Shape of the Behavior over Time The Strongest Lever is the Belief the Goal Came from, and It Moves by Showing a Failure It Cannot Explain The Sign of the Net Flow Decides Which Way a Stock Moves, Not the Size of Either Flow A Balancing Loop Settles at Its Goal, So Changing the Goal Beats Fighting the Loop Optimising Every Part Separately Usually Makes the Whole Perform Worse In Fixes That Fail the Quick Fix Works Now and Rebuilds the Problem Later Dependence Deepens Until the System Cannot Function Without the Symptomatic Fix