Implementation Details ---------------------- This page describes how our lab implemented the procedures required by the official protocol for the RRR. It also describes and justifies any additions to or departures from that protocol. You can view the official protocl and the main project page for this RRR using these links: - Official Protocol: [https://osf.io/ypd78/][1] - Main RRR project page: [https://osf.io/scu2f/][2] ---------- #### Experimenters #### Experimenters are: Prof. Timo Goeschl, Ph.D., Chair of Environemental Economics, University of Heidelberg. Johannes Lohse, Diplom Volkswirt, Ph.D. candidate at the University of Heidelberg. All sessions (expected size 12-20) will be run by same experimenter (Johannes Lohse). Mr. Lohse is familiar with the lab equipment and procedures. Furthermore, he has run several studies on time pressure in different economic decision tasks at the "AWI-Lab". ---------- #### Setting/Lab/Equipment #### The experiment will be run in several sessions with 12-20 participants each. The available workstations at the "AWI-Lab" ([https://economicexperiments.wordpress.com/awi-lab-2/][3] and [http://www.uni-heidelberg.de/fakultaeten/wiso/awi/forschung/awiexplab.html][4]) are separated by deviders from each other and the experimenter (see picture). ![Available Workstations][5] ---------- #### Sample, subjects, and randomization #### **Target sample size:** We will schedule 9-14 sessions, for a total target sample of 168 (84BL/84TP) participants. If, after completing those sessions and after exclusions and no-shows, we have reached our minimum required sample size of 152 (76BL/76TP) per condition, we will stop data collection. If either condition has fewer than 76 participants we will schedule additional sessions until we reach that minimum in both conditions. **Target sample demographics:** We will draw a sample from a population of volunteer participants at the "AWI-Lab" Heidelberg. Currently, the full pool consists of 1703 subjects among which roughly 700 qualify as naïve by having participated in no more than 3 experiments. Using the recruitment software ORSEE (Greiner, 2004), we will invite participants from this naïve population and moreover will exclude all subjects from recruitment, who have had prior experience with public good games at the lab. If required in order to meet the target sample size, we would also be able to recruit additional naïve subjects at the beginning of the term (October). Compensation will be based on decisions in the public good task (initial endowment: € 4) and a show-up fee (€ 3). This procedure will result in a standard convenience sample of students (approx. 55% female; 30% students of economics; 60% undergraduate and 40% graduate). **Minimum sample size after exclusions:** 152 (76BL/76TP) **Stopping rule(s):** We will run additional sessions, until both conditions reach at least 76 participants (after potential exclusions according to the protocol). **Randomization to conditions:** Participants will be randomly assigned to conditions by the provided Qualtrics Script. **Blinding to conditions:** Each subjects will also only be able to take part once (as ensured by ORSEE). Participants will not be able to speak to each other or observe the choices of other subjects. Instructions are administered via screen only and subjects will be informed about this procedure. **Exclusion rules:** Exclusions (if necessary) will be handled as described by the official protocol. No additional rules will be used. **Procedures for handling testing sessions for which the number of participants is not a multiple of 4:** As common practice at the lab, we will always invite 2-3 extra participants per session. Workstations (1-20) will be filled according to a randomly drawn card showing a number (1-20). Participants who draw a blank card will serve as reserve participants and wait. In case there are empty spots at the beginning of the experiment, reserve participants can take these spots until 12/16/20 workstation are filled. Reserve participants who cannot take part at the experiment will receive €3. They remain in the subject pool and can take part at later sessions. ---------- #### Software/Code #### We will be using the provided materials and have verified that they work with the lab equipment. ---------- #### Differences from the official protocol #### **Translation** Since testing will be conducted with German native speakers, materials will be translated into German by the experimenters from Göttingen. To check that the materials are equivalent in meaning to the English originals, researchers at the MPI will conduct a blind back-translation. Any differences between the original and the back-translation will be resolved with the other two German replication teams (MPI, Göttingen). [1]: https://osf.io/ypd78/ [2]: https://osf.io/scu2f/ [3]: https://economicexperiments.wordpress.com/awi-lab-2/ [4]: http://www.uni-heidelberg.de/fakultaeten/wiso/awi/forschung/awiexplab.html [5]: http://www.uni-heidelberg.de/md/awi/professuren/beheco/lab_pic1.png