Read the below paragraphs and discuss: What harm do minimum wages do?

For a long timeeconomistswhose median income, according to a survey of the American Economic Association (aea), is $104,000 a yearconsidered minimum wages to be harmful. A survey ofaeamembers in 1992 found that 79% of respondents agreed that a minimum wage increases unemployment among young and low-skilled workers. In an often fractious field, that is about as close to a consensus view as can be found. Although many economists recognised that low pay can indeed be a real problem, they argued that no pay was worse.

They were not the only people who thought so. The same argument was used by Republican politicians. In 1968, America's federal minimum wage stood at its highest level since first being applied in 1938. During the following two decades it fell, in real terms, by 44%. Though Jimmy Carter raised the wage in each of the four years he was president, keeping pace with inflation, Richard Nixon raised it only twice in six years and Ronald Reagan not once in eight. Some state and local politicians, mostly Democrats, tried to offset the fall by raising their minimum wages, creating a patchwork of different levels. The disparities this created allowed detailed empirical research on the policies' effects, and provided the means by which the economists' consensus would be undermined.

Not only did this see the conventional wisdom on minimum wages challenged in America; it also saw such policies spread elsewhere. Britain introduced a national minimum wage in 1998, and has increased it in recent years. Germany's came into effect in 2015. Around 90% of countries have some sort of legal wage floor, although enforcement practices vary widely. Economists now have lots of data with which to understand how minimum wages affect the economy in practice and, in the context of a promise by Democratic presidential candidate, Joe Biden, to raise America's federal minimum wage to $15, to argue about how high they can go.

The concern that minimum wages destroy jobs comes from the most basic of economic models: supply and demand. If labour is made more expensive, employers will probably want less of it. Textbooks state that, in the absence of a minimum wage, a worker is paid his "marginal product of labour", which means the value of what he produces. There is no room to deviate from this wage in either direction. If an employer tries to pay a worker less, a rival firm will poach him. If the government imposes a minimum wage that is higher than a worker's marginal product, the firm loses money by employing him. He is left jobless instead.

Reality is more complex. Firms do not know how much each worker contributes to their revenues. Few workers can find a new job at the drop of a hat. Yet the basic model reveals one important truth: the workers who are most vulnerable to losing their job as a result of the minimum wage are those whose productivity is lowthe very people the policy is designed to help.

More sophisticated theorising about labour markets recognises that they are not perfectly competitive. There is no single wage at which a worker has his pick of employers. As a result, firms probably pay workers less than their marginal revenue product. How much less depends on negotiations and who does best there depends on bargaining power. In this framework, the goal of the minimum wage is not to defy market logic but to stop firms in a strong negotiating position from squeezing their workers.

The upper bound on the minimum wage still applies: firms will not willingly employ workers at a loss. But below that ceiling, the effect of the minimum wage is ambiguous. It depends on a series of questions. Can a company replace its workers with machines? Can it raise prices and make its customers pay for the minimum wage? Does it face competition from foreign firms who face laxer rules overseas?

Consider a comparison between factories and restaurants. Logically, there would be little scope to increase manufacturing pay using minimum wages, because firms face stiff international competition, and jobs are constantly automated away. By contrast, jobs in restaurants are hard to automate and face no foreign competition. Any increase in costs affecting the whole sector should be passed on to consumers. Job losses should be lowerespecially if it turns out that consumers are willing to pay higher prices. So can one minimum wage do justice by both sectors?