The Effects of Increasing the Certainty of Punishment

Since 1993, Zurich's suburban transport systems have operated without attendants on the trains, and passengers' tickets were checked only sporadically. After increasing worries about crime and passenger safety on suburban trains, it was decided, in order to reduce fear of crime, to reintroduce attendants on all trains after 9 p.m. As well as dealing with order on the trains, these attendants had to check the tickets of all passengers. The programme was launched in June 2003, and once it was fully implemented the resources devoted to ticket checks and, thus, the number of passengers controlled after 9 p.m. rose by roughly 1500 percent. However, ticket checks remained stable and sporadic during day-time hours. The programme led to a dramatic reduction in fare-dodging on trains operating during the evening and, as an unexpected outcome, during day-time hours. The decline in fare evasion eventually levelled off. The results suggest that certainty of punishment works as a deterrent in a non-linear way, and that benefits from increased certainty can be maximized if checks are concentrated on critical hours and areas.