Drivers are randomly assigned an experimental condition, stratified along the dimensions of base location, gender, and years of service at the company. We construct reference groups in which driver performance on each comfort dimension is compared to colleagues with the same base location and treatment status. The comfort dimensions are disaggregated measures of driving behavior over which drivers have a strong direct influence, thereby making the feedback as concrete and useful as possible to the recipients.
At the start of each month, the company shares with us a summary of each driver’s performance during the previous month. We use this information to assess how a driver performed compared to his/her peers and to assign peer-comparison messages. Dependent on treatment assignment, a number of negative (positive) messages are provided if a driver belongs to the bottom 50% (top 25%) of the reference group.
Treatment T1 [0n0p] is the control condition with no peer-comparison messages. In treatment T2 [1n0p], one negative message is provided if drivers underperform on a particular dimension. That is, they are explicitly informed that they rank poorly compared to peers and are encouraged to improve. In T3 [1n1p], drivers additionally have a chance of receiving one positive message. In this case, they are made aware of their good ranking and are encouraged to keep up the good work. If a driver performs poor (or well) on multiple dimensions, one will be randomly chosen. Finally, in T4 [3n0p], drivers run the risk of receiving corrective feedback on all comfort dimensions.
Using T3 [1n1p] as an example, the precise (translated) text of the messages reads as follows:
In terms of taking corners, you belong to the top 25 percent of the bus drivers in your location.
You are doing excellent on this dimension!
In terms of braking, you belong to the bottom 50 percent of the bus drivers in your location.
You can improve on this dimension!
A printed version of the report is delivered around the 15th day of each feedback month via the team manager or pigeonhole. Drivers in the control condition receive the same feedback report but without the targeted messages, so as to account for general feedback effects. The report contains general feedback in the form of a letter score, ranging from A (highest score) to D (lowest score) on the comfort dimensions and fuel economy. Furthermore, it contrasts the overall score of the individual driver with the score of his or her base location.
In parallel, the company initiated a coaching program. Six experienced drivers (one for each base location) were recruited as coaches based on their track record of driving behavior. All coaches participated in a training on how to approach drivers and how to communicate feedback. Since coaches are bus drivers themselves, there is only limited time available for coaching activities (about one day every two weeks). Furthermore, because of the hop-on hop-off approach to on-the-road coaching, a coach’s previous session determines the choice set for the next. This makes random allocation of coaching sessions at the driver-trip level impossible. At the same time, it is next to infeasible for coaches to target specific drivers, also because coaches have no access to the individual feedback reports and hence cannot target drivers with poor scores. We will provide empirical support for the view that the assignment of drivers to coaching is the outcome of a quasi-random process.
In a coaching session, a coach rides along with a bus driver for a portion of the driver’s shift. This allows the coach to personalize the feedback and to direct attention to the driver-specific issues at hand. A session is not announced to the driver beforehand. The
coach writes down examples of what goes well and wrong and identifies obstacles that may hinder driver performance, such as sharp corners. Due to the presence of passengers, there is no or limited interaction between the driver and the coach during the ride. The coach
provides feedback once the trip is completed and passengers have left the bus. The trip is reconstructed using the written-down examples. Both personal and general advice are offered that focus on fuel consumption, punctuality and the ABC dimensions. Drivers are treated as equals and feedback is delivered in a constructive and positive manner.