Inflation is a general, sustained increase in the average price level across the economy — or, from the other direction, a persistent decline in what a dollar can buy. It is not one price going up (gas spiking after a hurricane) or a single sector overheating. True inflation means the whole basket of goods a typical household buys costs more this year than last.
Two fundamentally different forces can trigger it. Demand-pull inflation starts on the spending side: consumers and firms bid up prices because they have more purchasing power than the economy can satisfy. Cost-push inflation starts on the production side: when inputs get more expensive (oil, wages, raw materials), firms pass the higher costs on as higher prices. The policy prescription for each is different — applying the wrong one makes things worse.
Authors’ framing: No word strikes more fear into the hearts of central bankers than inflation. Left unchecked, it can have cataclysmic results for a society — from eroding savings to full hyperinflationary collapse. But a small, stable 2% annual rate is actually healthy, fueling modest demand growth without destabilizing expectations.
Economists use three main yardsticks, each watching a different part of the price system:
CPI — Consumer Price Index
Published by the BLS. Tracks the cost of a fixed market basket of goods and services a typical urban consumer buys: food, clothing, shelter, energy, transport, healthcare. The most widely quoted inflation measure in news and policy. Its limitation: the fixed basket doesn’t adjust when consumers substitute cheaper alternatives.
PPI — Producer Price Index
Also BLS. Tracks prices at the producer level — what businesses pay for inputs before anything reaches a consumer shelf. Because producer costs feed into consumer prices with a lag, the PPI is a leading indicator of future CPI moves. Governments use it to set policy before consumer inflation materializes.
PCE Deflator
Published by the BEA. Broader than the CPI — includes all goods and services consumed by households and nonprofits. Crucially, it adjusts for substitution: when beef gets expensive and consumers switch to chicken, the PCE basket shifts accordingly. The Federal Reserve prefers the PCE deflator for its 2% target because it better captures actual consumer behavior.
Getting the cause wrong is one of the most expensive mistakes in economic policy. Applying demand-reducing tools to a cost-push episode crushes GDP without fixing the underlying supply problem. Applying stimulus to a demand-pull episode pours fuel on the fire.
Demand-pull originates in too much spending power chasing too few goods. Its fingerprints: low unemployment, rising wages, rising consumer confidence, easy credit. The remedy is to reduce aggregate demand — tighten monetary policy, raise taxes, cut government spending.
Cost-push originates in supply-side shocks: an oil embargo, a crop failure, a supply-chain disruption that raises per-unit production costs. Its fingerprints: rising prices combined with falling output and rising unemployment (stagflation). The remedy is to let it run its course or address the underlying supply constraint — not to stimulate demand, which worsens the price pressure without restoring supply.
A small positive inflation rate (~2%) is beneficial: it creates an incentive to spend and invest now rather than hoard cash. At 2%, prices double roughly every 36 years — slow enough that long-term planning is undisturbed. Central banks fear the deflation trap (prices falling → consumers wait → demand collapses) almost as much as runaway inflation, which is why 0% is not the target.
Hyperinflation is inflation that exceeds 50% per month — a qualitative leap into a different world where money loses value faster than workers can be paid, barter replaces markets, and social order frays. It always involves a government printing money faster than the economy grows, usually to monetize debt it cannot otherwise service.
Read it as: The blue box is a stable economy. Two distinct amber triggers lead to two distinct red inflation outcomes — one where GDP rises (demand-pull) and one where GDP falls (cost-push / stagflation). Green boxes show the appropriate remedy for each. The red extreme at bottom right — hyperinflation — is where demand-pull goes if left completely unchecked and combined with debt monetization.
The Bakery Town thought experiment
Imagine a small town of 1,000 people whose only product is bread. Currently 1,000 loaves are baked per day and each costs $2.
Demand-pull scenario: The government sends everyone a $200 stimulus check. Demand for bread surges. The bakery can’t bake more loaves overnight — it’s at capacity. With more money chasing the same 1,000 loaves, the baker raises the price to $2.50. That’s demand-pull: spending power grew faster than productive capacity.
Cost-push scenario: A drought destroys 30% of the town’s wheat crop. Flour prices double. The baker’s input cost per loaf rises sharply. To stay solvent, the baker cuts output from 1,000 to 700 loaves per day and raises the price to $2.80. That’s cost-push: supply contracted and unit costs rose, pushing up prices while cutting output.
Notice: in the demand-pull case, more bread could be produced if the baker expanded. In the cost-push case, even with all the money in the world the wheat simply isn’t there. Spending more money in the second scenario just adds demand-pull pressure on top of an already supply-constrained situation — exactly the policy mistake to avoid.
Type to filter; press Enter to open