Teaching machine

The Jevons & Goodhart Machine

Two sliders. Two laws that break the "do more with less" promise. Drag them and watch the numbers do the opposite of what the business case assumed.

Jevons paradox · 1865

Cheaper per task, dearer overall

When each task gets cheaper, you do not do the same work for less. You do far more work, because more of it is now worth doing. Usage climbs faster than price falls, so the bill goes up.

Cost per task $1.00
← cheaperdearer →
Tasks / month 50,000 work you now take on
Monthly spend $100,000 the actual bill
Actual spend The saving you were promised

What this shows. The dashed line is the pitch: hold the work steady, cheaper tokens, smaller bill. The amber line is what happens when people find new things worth doing at the lower price. That is Jevons. "More" is the expensive part.

Goodhart's law · Strathern 1997

Optimise the metric, lose the outcome

Push hard on an assurance metric and the metric obeys. But once a measure becomes the target, people hit the number without doing the thing it stood for. The dashboard goes green while real assurance drifts.

Pressure on the metric 20%
hands offhit the number at all costs
Dashboard score 36 what leadership sees
Real assurance 57 what is actually managed
Unmanaged risk (the gap) 0 measured minus real
Dashboard score Real assurance The gap

What this shows. Beer's test: the purpose of a system is what it does. Crank the pressure and this governance system produces a green number, not safety. The green number is now its real job.

All figures are illustrative and synthetic. A teaching model, not a forecast: the curves are deliberately simple so you can feel the mechanism.

Paired with the article Doing More With Less Is a Trap.