I’ve never worked in the food service industry but I’m fascinated by the psychology of tipping. In the U.S. tipping is voluntary but expected; partly due to social convention and partly because food servers depend on tips to make a living. Because U.S. food servers are required to pay income tax on the value of the food, many servers need an 8% tip just to break even.

According to research studies, many of the factors that influence the size of a tip are outside servers’ control. As might be expected, diners leave larger tips when the restaurant is elegant or in an urban area, when the food quality is high, and when the weather is pleasant. But the research also shows that tip size is affected by the size of the dining party (larger groups tip more), the method of payment (credit cards yield higher percentages than checks or cash), and by the amount of alcohol consumed (not surprisingly). Controversially, ethnicity appears to influence tipping behavior as well.

On the other hand, servers can obviously impact the size of a tip. According to studies, introducing yourself by name increases tip size from 15% to 23%, touching diners on the shoulder when delivering the bill increases tips from 12% to 18%, and supplying an unexpected after-dinner mint improves the tip from 19% to 28%. Read the full blog post here.