Part 7 · 1 chapters · ~10 min
Systems Thinking
Stocks and flows, reinforcing and balancing loops, delays that cause overshoot, second-order effects found by asking "and then what?" twice, leverage points from parameters to goals, and Conway's law, with the clearance letter and familiar engineering loops as examples.
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Loops, delays and "and then what?"
draw the loop before you change the system
- Name the stocks (backlog, debt, users, trust) and the flows that change them.
- Find the loops: which ones amplify and which ones balance? Who is in them?
- Mark the delays: where does the effect of an action arrive late?
- Ask "and then what?" twice for the change you propose.
- Look for leverage in goals, rules and information before parameters.
| situation | loop | intervention with leverage |
|---|---|---|
| incidents leave no time for reliability work | reinforcing, downward | an error-budget policy (a rule) that pauses features when the budget is spent |
| flaky tests get retried, so nobody fixes them | balancing that hides the cause | publish flake rates per owner (information); quarantine with an expiry date (rule) |
| teams duplicate components because sharing is slow | reinforcing divergence | a design system team with a fast contribution path (information flow and a goal) |
| manual letters create support load | a constant inflow to a stock | self-serve generation removes the inflow, then plan for rising demand |
read
Donella Meadows, Thinking in Systems (short) and her essay "Leverage Points: Places to Intervene in a System". Both explain why the obvious fix often makes things worse, and they give you language for saying so in a design review.
SYSTEMS THINKING
stocks and flows, feedback loops, delays and the second-order effects that make good changes go wrong
swipe the figure sideways, or tap expand for full screen
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stocks, flows
Stocks and flows: a support backlog is a stock; new tickets are an inflow, resolved tickets an outflow. The stock only falls when outflow exceeds inflow. The 249 manual clearance-letter issues a month were an inflow; automating the letter cuts the inflow instead of speeding up the outflow.