Tipping is an important economic phenomenon, involving about $47 billion a year in the US food industry alone, and trillions of dollars across different occupations and countries over the years. Moreover, tipping is a major source of income for millions of workers. This article discusses the...

Some economists believe that social norms are created to improve welfare where the market fails. I show that tipping is such a norm, using a model in which a waiter chooses service quality and then a customer chooses the tip. The customer's utility depends on the social norm about tipping and...