Every society must answer three basic economic questions: what to produce, how to produce it, and who gets it. Different economic systems answer them in different ways.

Types of economic systems

• Traditional economies answer by custom: people do what their parents did, and goods are shared by long-standing rules.
• Market economies answer mainly through private ownership and voluntary exchange, coordinated by prices.
• Command economies answer through central planning by the state, which owns most productive property and sets output targets and prices. The Soviet Union ran such a system from the late 1920s until its collapse in 1991.
• Mixed economies combine markets with significant government roles: regulation, taxes, public services and social insurance. Nearly every modern economy is mixed; countries differ in the balance.

Two thinkers frame the classic debate. Karl Marx argued in the nineteenth century that capitalism exploits workers and is prone to crises, and that the means of production should be owned in common. Friedrich Hayek argued in the 1940s that central planners cannot gather the knowledge spread among millions of people, which prices convey, and warned that concentrated economic power threatens freedom. The record of the twentieth century, including the weak performance of most planned economies and China's turn toward markets after 1978, has shaped how economists judge these ideas. Defenders of a larger state role point in turn to the rapid industrialization some planned economies achieved and to market crises such as the Great Depression and the 2008 financial crisis. Most economists now accept a large role for markets while disagreeing about how large government's role should be.

Thinking like an economist

Whatever system you favor, a few habits help with any public question.

1. Look for trade-offs. Every policy uses scarce resources that could go elsewhere. Ask: what is given up, and by whom?

2. Look for unintended consequences. People respond to incentives, sometimes in unexpected ways. The French writer Frédéric Bastiat, in an 1850 essay, urged readers to consider not only “that which is seen,” the obvious effects of a policy, but also “that which is not seen,” the effects that are harder to notice. If a boy breaks a shop window, onlookers may console the owner that at least it makes work for the glazier. What is not seen is the new shoes or book the owner would otherwise have bought. Treating destruction as a gain is the broken window fallacy.

3. Ask for evidence, and handle it carefully. Correlation is not causation: two things moving together does not prove that one causes the other. Economists increasingly use natural experiments (comparing similar places affected differently by a policy) and randomized controlled trials, the method behind the 2019 Nobel prize in economics awarded to Abhijit Banerjee, Esther Duflo and Michael Kremer for their work on poverty.

4. Separate facts from values. Positive statements describe how the world is and can be tested: “A higher tax on fuel will reduce fuel use.” Normative statements say how the world should be: “Fuel should be taxed more.” Many economic arguments mix the two. Agreeing on the facts does not settle the values, and sharing values does not settle the facts.

5. Think at the margin and over time. Ask what happens with a little more or a little less, and over months and years, not just today.

These habits do not tell you what to conclude, and economists who share them still disagree about a great deal. They make your conclusions sturdier, and help you understand why reasonable people disagree.

Worked example: a storm and the price of generators

A hurricane knocks out power across a region for a week. Stores raise the price of portable generators from $500 to $1,500. Angry residents ask the town council to ban price increases during emergencies. Apply the five habits.

Trade-offs. A ban protects buyers from high prices, but at a cost: at $500, far more people will want generators than there are generators to sell.

Unintended consequences. What is seen: fair prices for the lucky first customers. What is not seen: generators that suppliers in other regions would have trucked in if prices covered the extra cost and risk; families who need one for a medical device but arrive after the shelves are empty.

Evidence. What actually happens in places with and without such laws? Do supplies arrive more slowly where prices are capped? Do high prices mostly reflect real costs, or opportunistic profit? These are empirical questions.

Facts and values. Many people feel that profiting from a disaster is wrong, whatever its effects on supply. That is a moral view, not a factual error. An economist can point out consequences but cannot tell residents how much weight to give fairness versus availability.

Margins and time. In the first days, few new generators can arrive whatever the price; over a week, high prices may draw in many more.

Possible compromises include allowing price rises that reflect higher costs while banning extreme markups, or letting prices rise while the town buys generators for vulnerable households. Thinking like an economist does not settle the debate. It makes clear what each option costs, and who pays.