The field experiment is conducted in public transport in Lyon (France) by teams involving a research assistant and a professional actor. The experiment consists of two stages. The first stage takes place on board buses and trams and produces two main natural conditions. In the Inspection condition, a targeted passenger has been controlled by ticket inspectors from the transport company during his or her journey, whereas in the No-Inspection condition no ticket inspection occurred. The occurrence of a ticket inspection is only determined by the public transport company.
The second stage takes place when the targeted passenger gets off the vehicle, on the street. A professional actor, who is part of the experimental team, walks behind the targeted passenger and suddenly bends down to seemingly pick up a 5 euro banknote on the ground. The actor then calls the attention of the targeted passenger by asking whether he or she had lost a 5-euro banknote. We measure intrinsic honesty by recording whether the passenger takes or not the banknote. The actor has to use his or her mobile phone as an audio recording device when playing the scene on the street. We use these recordings to verify that the actors followed the protocol that we gave them to play the scene and as a robustness check to ensure that any minimal deviation from this protocol did not affect the internal validity of our results.
In our experiment there are three treatment conditions (Inspection, No Inspection, No Inspection-Audience) and two categories of passengers (fraudsters vs. non-fraudsters). The No Inspection-Audience condition is similar to the No Inspection condition, except that the research assistant walks by the actor when the latter plays the scene.
The research assistant has to identify the target passenger in the bus/tram (among the first few passengers entering the vehicle, the target passenger is the first of these passengers getting off the bus/tram). The research assistant has also to collect information for each observation: the name of the actor playing the scene, the time of the day, the weather, the treatment condition (Inspection, No Inspection, No Inspection-Audience), the name of the bus/tram line where the subject travelled, whether the subject validated a ticket, a pass or nothing, the approximate number of people on board the bus/tram, whether someone could notice the scene played in the street, whether the subject took or not the 5-euro banknote, the gender, estimated age, estimated economic status based on appearance, and ethnicity of the subject, and whether he or she wore religious symbols. In the Inspection condition, additional information is collected: the number of controllers, whether the inspection was conducted at the tram/bus stop or on board, whether the controllers wore uniform or civil clothes, the gender of the controller who inspected the subject, and, if the subject was a fraudster, whether he or she paid the fine immediately, and whether he or she had an emotional or aggressive reaction.