In collaboration with DiDi, we will send out text messages telling drivers in four cities that they can participate in a team contest. The drivers can choose to participate or opt out. If they opt out, they will not receive further messages. If they opt in, they will participate in the following multi-phase field experiment:
Phase 0: team formation (one week): Drivers will join teams using the Didi team app.
Phase 1: warm-up contest (one week): The experimenter assigns teams to contests, each of which consists of five teams. The contest runs for seven days. At the end of the week, the team with the highest cumulative revenue wins the cash prize, whereas the four losing teams receive no prize. The winning prize is kept constant within the same city, and adjusted based on city-average driver revenue across cities.
The social information regarding the daily revenue of each driver and the corresponding ranking within a team, similar statistics of competing teams are accessible through the app as within-team and within-contest leaderboards.
Phase 2: leaderboard (three weeks): This phase is designed to maintain team identity in the treatment, but not in the control. The intervention is limited to social information, without monetary incentives. It will last for three weeks. Prior to the start of phase 2, within each city, the experimenter sorts leaderboards in descending order of their total revenue during the 14 days prior to the start of the experiment, and group each 9 consecutive leaderboards into a stratum. Within each stratum, the 9 leaderboards are randomly assigned to each of the three experimental conditions, including the control group, the placebo group, and the leaderboard treatment group.
Phase 3: surprise contest (one week): After the second phase, every team is again called to participate in a surprise week-long contest for a cash prize, as in the first stage. This contest has not been announced before. This phase is designed to evaluate the effects of the leaderboard on team identity and productivity. Everything remains the same as in the warm-up contest.
Phase 4: post-experiment survey: At the end of the three contest phases, the drivers will each receive a survey which evaluates their sense of belonging to their team as well as to the organization (DiDi).