Do people tip strategically, to improve future service? Theory and evidence

A central question about tipping is whether people tip strategically, to improve future service, or only because tipping is a social norm. I present a theoretical model that incorporates psychological utility associated with tipping (because it is a social norm) and allows tipping to be motivated also by future service considerations. The model predicts that if future service is a reason for tipping, the sensitivity of tips to service quality should be higher for repeating customers than for non-repeating ones. Surveys of 597 restaurant customers are analysed and suggest that future service is not a reason for tipping.