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 #### *Marco Piovesan, Associate Professor, Department of Economics, University of Copenhagen. Co-Director of the Center for Experimental Economics. Marco has conducted several experiments in the lab and in the field. His papers have been published in academic journals including the American Economic Review, Journal of Experimental Psychology-General, Economics Letters, PLoS ONE, Journal of Economic Behavior and Organization, Journal of Economic Psychology, Scandinavian Journal of Economics and International Review of Economics* *Erik Wengstrom, Associate Professor, Department of Economics, Lund University. Erik has conducted several experiments in the lab and over the internet (iLee project). His papers have been published in academic journals including the American Economic Review, Economics Letters, Management Science, Journal of Public Economics, Journal of Risk and Uncertainty, Journal of Economic Behavior and Organization, Scandinavian Journal of Economics.* *Felix Døssing, PhD student at the University of Copenhagen. Has previously conducted lab experiments on the effect of cognitive load on cooperation.* ---------- #### Setting/Lab/Equipment #### *The LEE is a state-of-the-art facility devoted to research and teaching in experimental economics. The laboratory facilities consist of 2 rooms for participants (with a capacity of 55 participants), a control room (for monitoring and payment), and an office with work space for researchers and students. LEE is part of the Centre for Experimental Economics (CEE) and is hosted by the Department of Economics at the University of Copenhagen.* *We plan to collect at least 150 observations (75 in each of the two conditions. Each session will have 24 participants. The experiment will be computerized and run according the procedure of the Laboratory for Experimental economics of the University of Copenhagen. In particular we do not allow for deception and subjects decisions will be kept anonymous.* ---------- #### Sample, subjects, and randomization #### **Target sample size:** *We plan to collect at least 150 observations (75 in each of the two conditions. We will schedule a total of 10 sessions with 24 participants in each session.* **Target sample demographics:** *Students at the University of Copenhagen without prior experience with public goods experiments and under the age of 35. Between 20% and 80% female.* **Minimum sample size after exclusions:** *150 participant (75 in each condition).* **Stopping rule(s):** *We plan to carry out 10 sessions with about 24 participants in each session. This will almost certainly result in a sample size, which is above the minimum requirement. Should this turn out not to be the case, we will run additional sessions until the sample size exceeds 150 with 75 in each to the two conditions.* **Randomization to conditions:** *Participants will be randomly assigned to conditions by the provided Qualtrics Script.* **Blinding to conditions:** *The experiment will be carried out in a professional facility for conducting economic experiments. The facility is equipped with blinders, which ensure, that the participants are unaware of the instructions and actions of other participants.* **Exclusion rules:** *We will be using the same exclusion rules required by the official protocol.* **Procedures for handling testing sessions for which the number of participants is not a multiple of 4:** *In each session the experiment will be followed by a 10 round public goods game, which is carried out for the purpose of teaching. Should the number of participants not be a multiple of 4, the "extra" participants will be asked to wait outside the lab, while this experiment is carried out. Afterwards they will be invited to participate in the teaching experiment.* ---------- #### Software/Code #### *We will be using the provided materials, including the Qualtrics scripts, and have verified that they work in our laboratory.* ---------- #### Differences from the official protocol #### *The only departure from the official protocol is, that the experiment involves danish currency DKK rather than US dollars. The conversion of the currency is done using the OECD Purchasing Power Parieties (PPP) index for GDP. According to this table, 1 dollar is equal to 7.56 DKK. In order to preserve round values we will be using the following (the excact conversion is shown in paranthesis): Show-up fee 40 DKK (37.8 DKK), endowment 30 DKK (30.24 DKK).* [1]: https://osf.io/ypd78/ [2]: https://osf.io/scu2f/