Every February, the price of red roses rises sharply before Valentine’s Day. This is a example of supply and demand. for roses increases suddenly, the supply cannot grow as , because roses take to grow. When many buyers for a limited number of , sellers can more. After February 14, demand , and prices return to .

Sometimes governments try to protect consumers by setting a maximum legal price for a product, known as a price ceiling. The goal is understandable: to keep essential goods affordable. Economists, however, warn that price ceilings often have unintended effects.

When the legal price is set below the level at which supply and demand would balance, buyers want more of the product than sellers are willing to offer. The result is a shortage. Because price can no longer decide who gets the product, other methods take its place: long lines, waiting lists, or personal connections.

A well-known example occurred in the United States in the 1970s, when price controls on gasoline were combined with disruptions in supply. Drivers waited in line for hours at gas stations, and some stations ran out of fuel entirely. Rent control in some cities provides another debated case. It can help existing tenants stay in their homes, but critics argue that it may discourage landlords from building or maintaining apartments over time.

None of this means that price ceilings are always wrong. Many economists argue, however, that if the goal is to help poor households, direct support such as cash assistance may achieve it with fewer side effects. The debate shows how a policy that seems simple can have complex consequences.