It is said that when the Nobel Prize in economics was first established, prizes were given for using economics to teach people things they didn’t already know, e.g., that economic growth might increase inequality, that depressions are caused by central banks, that macroeconomic stabilization policy doesn’t work, etc. Now, prizes are given to economists who teach other economists things that regular people already know — politicians are self-interested, you shouldn’t put all your eggs in one basket, institutions matter, different people know different things, etc.

On many markets, buyers and sellers do not always make contact with one another immediately. This concerns, for example, employers who are looking for employees and workers who are trying to find jobs. Since the search process requires time and resources, it creates frictions in the market. On such search markets, the demands of some buyers will not be met, while some sellers cannot sell as much as they would wish. Simultaneously, there are both job vacancies and unemployment on the labor market.