Randomization Method
The first study is leaderless, following Weidmann and Deming (2026). It has one control and one treatment group. We will estimate the team player index. For each participant, we estimate this index.
The Teamplayer Index is a novel measure of individual performance in the context of collective problem solving. A detailed description of how the index is conceptualized and calculated is provided in the attached Statistical Analysis Plan.
In brief: the Teamplayer Index for participant i is the average performance of the groups to which i was allocated, conditional on the individual skill of each of i's groups. Group performance is assessed using the image recognition task, adapted from Fügener et al. (2022).
The experiment has two stages. In the first stage, participants in the control group will individually complete 30 image-recognition tasks. In the treatment groups, players will complete the 30 image-recognition tasks with the help of AI. At the end of stage 1, participants will complete a self-reflection on providing a point estimate and a 90% confidence interval for the correct number of questions in stage 1.
In the second stage, participants will complete tasks for group image recognition. Three players form a group, and they will finish 4 rounds of image recognition tasks, in total 4 * 3 = 12 group image recognition tasks. Each round has 3 questions; the group composition does not change within a round. Following Weidmann et al. (2026), the randomization rule is that players who have cooperated before will never meet again in subsequent rounds.
For example:
- The n participants in each session are divided into three equal blocks of size n/3, based on their overall score in stage 1 (without leader experiments) and part 1C (with leader experiments) [if n is not a multiple of three, excess participants are paid for their time and asked to return to another session]. Blocks can loosely be thought of as ‘high’, ‘medium’, and ‘low’ in terms of individual skill.
- There are three bags, one for each block. Each bag has n/3 balls, marked with a letter. Bags have consecutive letters. For example, in a session of 9 people, the bag for ‘high’ performance will have balls labeled A, B, C; the ‘medium’ bag will have balls labeled D, E, F; and the final bag will have balls labeled G, H, I.
- Each participant draws a ball. This ball defines their 2 groups for that session. To return to the example of a 9-person session, allocations would be as follows: first set of groups: {ADG, BEH, CFI}; second set of groups: {AEI, BFG, CDH}.
In the control group, they will first submit their answers and have the chance to discuss the questions with their teammates via a live chatbox. In the treatment group, players will first submit their answers with the help of AI and be given the chance to discuss the questions with their teammates via a live chatbox. Finally, a randomly selected representative will submit the answer that the whole group agrees on. At the end of stage 2, participants will complete a self-reflection on providing a point estimate and a 90% confidence interval for the correct number of questions in stage 2.
In the second study, we follow Weidmann et al. (2026) on the randomization method. The study has 2 control groups (C1: no AI random leader; C2: no AI self-promoted leader) and 6 treatment groups (T1: AI random leader; T2: personalized AI random leader; T3: certainty AI random leader; T4: AI self-promoted leader; T5: personalized AI self-promoted leader; T6: certainty AI self-promoted leader).
We first randomize sessions to either the ‘self-selection' or ‘random’ conditions. Participants in the self-selection condition rate their preference for being a manager for the remainder of the experiment on a scale of 1 to 10. Those with the strongest preference are assigned to be the manager (if there is a tie, roles are randomized). Those in the ‘random’ condition will be randomized to their role.
We also randomly assign each manager to eight different three-person teams over the course of the experiment. Workers are randomly assigned to managers, with two constraints: if possible, we avoid groupings in which workers are assigned to a manager they have worked with before. Second, workers are allocated to a manager at most once.
In the first stage, participants will individually complete 18 image-recognition tasks. These 18 tasks are divided into 3 parts. Part 1 has 6 questions, and these are done without AI. Part 2 has 6 questions, and these are finished with AI. Part 3 has 6 questions. At the end of stage 1, participants will complete a self-reflection on providing a point estimate and a 90% confidence interval for the correct number of questions in stage 1.
In the second stage, participants will complete tasks for group image recognition. Three players form a group, consisting of 1 leader and 2 workers, and they will finish 4 rounds of image recognition tasks, in total 4 * 3 = 12 group image recognition tasks. Each round has 3 questions; the group composition does not change within a round.
Following Weidmann (2024), the randomization rule is that players who have cooperated before will never meet again in subsequent rounds. In the control group, leaders will first submit their answers and then discuss the questions with their teammates via a live chatbox. In the treatment group, leaders will first submit their answers using a specific AI and then have the chance to discuss the questions with their teammates via a live chatbox. Teammates cannot chat with each other and have no access to AI throughout stage 2.
Finally, a randomly chosen representative in the random-leader treatments and a self-selected leader in the self-promoted treatments will submit an answer after discussing with the team members. At the end of stage 2, participants will complete a self-reflection on providing a point estimate and a 90% confidence interval for the correct number of questions in stage 2.