FAQ - Frequently Asked Questions

General information on experimental economic research and the KD²Lab

Experimental economics is a research method that investigates economic theories, models and issues with the help of controlled laboratory and online experiments as well as field experiments.
In a controlled experiment, study participants make decisions on the computer within the framework of a clearly defined, specific economic situation.
The study participants are paid depending on their decisions and those of other participants. The anonymized data obtained in this way are then analyzed both qualitatively and quantitatively for the purpose of investigating and answering economic questions.

One goal of experimental economic research is to gain a better understanding of the decision-making behavior of individuals, since the predictions of economic theory often do not match the actual observed behavior. The data obtained can thus be used to test existing theories and to develop new theories. Furthermore, experiments are also used, for example, to extensively test new market institutions - even before they are introduced in practice - for their functionality.
The results of the experiments are published in articles of scientific journals or in scientific papers, i.e. dissertations or post-doctoral theses. We provide information on our website about where the results of specific experiments have been published. Publications for which the data collection was performed in KD²Lab are also linked in the KIT Library under the tag "KD2Lab".

To date, the projects at KD2Lab deal, among other things, with the determinants of solidary behavior, the analysis of different market and auction designs, but also the impact of different information systems and their design. In addition, studies with and without the acquisition of biosignals (e.g. eye-tracking, EEG, ECG, wearables) are taking place.

Click here to plan your journey to the KD²Lab. The address is:
Karlsruhe Institute of Technology
Fritz-Erler-Straße 1-3 (Zähriger-Haus)
Building-No. 01.85.

The KD²Lab is located near the Kronenplatz tram station. You can access the lab via a staircase from Fritz-Erler-Straße as well as via the pedestrian bridge between Waldhornstraße and Kronenplatz. You will recognize the lab by a sign reading "Karlsruhe Decision and Design Lab" at the entrance. The lab allows barrier-free mobility and can be reached via elevator.

Participation in an online experiment does not require physical attendance in our lab. Information on whether the study takes place as an online or laboratory experiment can be found in the invitation email.

Compensation & payment

The income generated by you in the KD²Lab basically represents income (among others in the sense of the EStG, BAföG etc.). You are required to report this income to your relevant authorities (tax office, health insurance, BAföG or housing subsidy office, etc.). With regard to your tax obligations, your responsible tax office or tax advisors can usually provide you more information.

Yes, registration in the system and signing up for experiments is free!

In general, there is a compensation for each experiment. However, the amount of payment usually depends on your decisions and the decisions of other participants. For scientific reasons, we do not give any information about the exact expected value and the upper and lower limits. Nevertheless, we pay attention to an adequate compensation.

Payoffs in most experiments are determined by your choices and those of other participants.

You are expected to arrive at the lab prior to the specified time to allow a timely start of experiments. Since the experiments are very expensive to run, we cannot wait for participants who arrive late, as this will jeopardize the conducting of experiments. Please take into account that all experiments are designed for a certain number of participants. If even one test person is absent, experiments often cannot be carried out.

The payment will be made by SEPA bank transfer. Please have your IBAN account number ready.

Prerequisites for participants

Many studies are conducted in German or in English, therefore a very good knowledge of German or English is mandatory to understand the instructions or the procedure. A thorough understanding of the instructions will also increase your chances of receiving a higher payout. The language requirements and further instructions can be found in the invitation email.
No further prior knowledge is required.

  • You are at least 18 years old at the time of registration.
  • You have at least very good knowledge of at least one of the following languages: German, English.
  • You are enrolled as a student at a university. As soon as you finish your studies, you are no longer eligible to participate.
  • You have unrestricted or corrected vision and hearing and are able to work on a PC without aids or assistants, i.e. you can independently read texts on the screen and make entries with the mouse and keyboard.
  • At the time the conditions of participation are drawn up, a bank account in the SEPA area is required for payment of the expense allowance. If other payment channels are opened, this will be communicated in due course.

Registration participants database

Registration takes place directly on this page under "Register".

When registering, the first and last name as well as the date of birth according to the ID must be provided for clear identification. Registration under a false name or with a false date of birth is not permitted.

This information is crucial for planning scientific studies, especially in deciding for/against inviting experimental participants. Additionally, you will not be invited to participate in experiments if we determine that the information you have provided is incorrect. If you do not want to provide certain information, please leave the corresponding fields blank. However, providing additional information will increase your chances of being invited to participate in an experiment.

Registering with more than one e-mail address is not permitted. In case of multiple registration, it might occur that one person participates in a series of experiments more than once, thus falsifying the results. Should you be registered for an experiment with different e-mail addresses, we reserve the right to exclude you from participating in that experiment without compensation.

If you wish to change your email address, you can do so using the link attached to our emails. This will lead to your profile, where you can change your address.

Receiving & accepting invitations

To participate in an experiment, you must first register in our participant database. After successful registration you will be considered for invitations by the system. However, it may take a few weeks until the first invitation in individual cases, please be patient. The invitation will tell you the type, time and, in the case of laboratory experiments, the location for the experiment.
Since it also happens that experiment participants do not show up for an experiment despite binding registration, but we have to make sure that there are enough experiment participants, usually more participants are invited than are necessary for the experiment. It may therefore happen that you are "only" a substitute participant. In this case, you will receive an expense allowance right at the beginning of the experiment and will not participate in the experiment. However, in this case you can still register for later sessions of the same experiment.

It is not allowed to be represented by other participants. Only those who have been invited and have registered bindingly may take part. Therefore, it is prohibited to forward invitations to others or to be represented by others! However, you are welcome to encourage other students to register in the participants database.

In some experiments, we require participants that meet certain criteria. Therefore, we kindly ask you to only show up for experiments where you have personally received an invitation and have registered. You will otherwise not be able to participate.

Depending on the experiment, we need different groups of participants who meet certain requirements (e.g. participation in similar studies in the past,...). Within these groups, some of the possible participants are randomly invited for an experiment. Always more participants are invited than needed for the experiment. Of course, it can happen that some are randomly selected more often than others. Unfortunately, this cannot be avoided. In our experience, everyone in the participant database is invited with a similar frequency throughout the year.
If you have frequently failed to show up unannounced for experiments, this may also be a criterion used to filter study participants in order to prevent experiments from not being carried out due to an insufficient number of participants.

Most of the experiments are performed on different dates. Therefore, you can only register for one date per experiment.

The following applies: One registration is possible per invitation email.

Experiments procedure

The experiments take place irregularly and last differently depending on the experiment. On average, the execution of an experiment takes 1-2 hours. However, participants who are invited to an experiment always find out in advance in the invitation email when an experiment will take place and how long it will last.
Also always bring the time announced in the invitation. Leaving the experiment early is not possible and would have far-reaching negative consequences.

At the beginning of each experiment, study participants are given detailed instructions about what they should do and which decision-making problem they will face. In many cases, consent and data protection documents must also be signed in order to protect the participants. You do not need any special knowledge, or prior experience, in order to solve the tasks. However, please note the participation requirements for the respective experiment.

Very important: Our experiments run exactly as stated in the instructions. You will never be lied to or be manipulated! Doing so violates our laboratory rules and is, furthermore, fundamentally forbidden in experimental economic research.

In principle, no drugs or medications are administered in experiments conducted at the KD²Lab. Should there be experiments involving medication in the future, all participants will be informed via the invitation in order to be informed before deciding whether or not to participate.

Laboratory experiments take place throughout the year, usually on weekdays between Monday and Friday from 10:00 to 18:00. Exact dates will be provided to you with the invitation email, allowing you to choose a date that suits you. Using your account, you can then bindingly register for this date.

Signing off experiments

Signing off an experiment is generally not provided. Please double check that you are available for an experiment PRIOR to registering for an experiment.

Should you become ill or be unable to participate due to other circumstances, be sure to respond to your invitation email as SOON AS POSSIBLE. The lab team will then sign you out of the experiment.

After you have signed up for an experiment, please be sure to attend. Compensation comparable to yours is paid to several hundred other participants in some experiments. Canceling an experiment due to too few participants is therefore associated with high financial consequences for researchers.

For each absence after registration for an experiment (without timely cancellation by the experiment organizers or without giving a valid reason), a minus point will be added to the participant's personal account. The more minus points participants have, the lower their chances of being invited for further experiments. Once your account receives three minus points, you will not be invited to participate in another KD²Lab experiment.

Unsubscribing from the participants database

All participants can determine at any time on the personal page under "My data" that they do not wish to receive any further invitations to experiments. You can also set your status to "inactive" if you do wish to participate in experiments at a later date. Upon request of participants, personal data will be deleted without restriction. To do so, send an e-mail to the team address: team∂kd2lab.kit.edu with the note "Löschen" ("Delete").

It is your right to have your data permanently deleted from the participants database. To do so, send an e-mail to the team address kd2lab∂kit.edu with the note " Löschen" ("Delete"). Subsequently, all of your personal data will be deleted. You may also have your profile set to the status "inactive" in case you want to participate in experiments at a later date. In that case, we will switch your data record back to the status "active" on your instruction.

Data protection

Please use the link attached to all our emails. It will take you to your profile. There, you can enter the new address. Please do not register additionally with the new mail address!

You are not allowed to sign up with a friend’s email address. Each person in our database must provide their own unique email address.

  • When conducting experiments, data are generated by the decisions to be made by the study participants.
  • These data are analyzed scientifically. In the process, the decision data is anonymized and cannot be assigned to any person. Participation in the experiments is anonymous in this sense.
  • The generated, anonymized data are used for the preparation of scientific research papers and presentations. These papers will be published.
  • The experimental data will not be linked to the data in the participant database. There is no linkage between the data generated in the experiment and the data in the Participant Database. The collection of study participants' names in the experiment is permitted solely for the purpose of generating the disbursement list and must be deleted thereafter. By participating in the experiment and signing the participant agreement, you accept the anonymized use of the experimental data for the research purposes of our researchers.

It is your right to have your data permanently deleted from the participants database. To do so, send an e-mail to the team address kd2lab-team∂kit.edu with the note " Löschen" ("Delete"). Subsequently, all of your personal data will be deleted. You may also have your profile set to the status "inactive" in case you want to participate in experiments at a later date. In that case, we will switch your data record back to the status "active" on your instruction.