Even when the service is considered to be poor consumers will still leave a tip for the poor standards; however, the tip will be reduced or low to reflect the substandard service. This suggests that tipping is effective when the consumer can rate service by tip amount. .
Orn B. Bodvarsson, a highly accredited economist, explains in the article "Why do diners tip: rule-of-thumb or valuation of service?", that service quality significantly effects tip size and when servers can expect a higher tip which implies tipping is economically efficient. He conducts a study utilizing 247 diners in a restaurant and its servers in Central Minnesota with a survey and several variables. The survey includes several questions about service with different variations and rankings. Bodvarsson points out how similar studies are severely biased and only gather data from the consumer, rather than the consumer and the worker. His study includes both the consumers' and the servers' data. A portion of the study that is unlike the others is the percentage tips and the supply of service quality is concurrently factored. Previously, only the tip amount was factored. Bodvarsson states, "This study has shown that when corrections are made to this bias, the relationship between service quality and tips is strengthened considerably". He raises a point that economists did not consider in similar previous case studies. Bodvarsson states, "The most important finding is that there is strong two way relationship between customer evaluations of service quality and percentage tips; server expectations of tips influence the supply of service quality and service quality influences tip amounts". He explains that this is an important finding because not only is the customer anticipating a tip, the servers as well assess diners when deciding the level of service quality and professionalism to provide, in return ultimately induces the tip rewarded.
