Punctuated Equilibrium Analysis

A policy image is the prevailing way an issue is understood and portrayed, combining factual and emotional content — for example, nuclear power as 'progress' versus 'danger'. A policy venue is the institutional arena with authority to make decisions on the issue, such as a particular committee, agency or court. Stable policy monopolies rest on a dominant image confined to a sympathetic venue; change typically comes when the image is contested and the issue migrates to a new venue, breaking the monopoly.

Because political institutions process information disproportionately rather than smoothly. Friction, attention scarcity and institutional inertia cause most issues to receive only tiny adjustments most of the time, while occasional surges of attention produce very large changes. The result, across many issues, is a distribution with an unusually tall central peak (many minimal changes), weak shoulders (few moderate changes) and fat tails (some huge changes) — the leptokurtic signature that empirically distinguishes PET from theories predicting proportionate, incremental adjustment.

PET both incorporates and challenges incrementalism. It accepts that policymaking is incremental most of the time, during the long equilibria when negative feedback keeps change small. But it argues that incrementalism is only part of the story: the same system periodically produces large, non-incremental punctuations through positive feedback. PET thus reconciles the observation of routine small adjustments with the equally real occurrence of dramatic reversals, which pure incrementalism cannot account for.