Changes

In order to observe the GDPR, experimental data is preferable saved anonymously. This poses a problem if the a participant to the experiment wishes to identify themselves. This could occur for instance because the participant wishes to revoke the data submitted to the experiment. If you want to make this possible you can follow the approved procedure below.

In order to observe the GDPR, experimental data is preferably saved anonymously. This poses a problem if a participant to the experiment wishes to identify themselves. This could occur for instance because the participant wishes to revoke the data submitted to the experiment. If you want to make this possible you can follow the approved procedure below.

== Procedure ==

== Procedure ==

* Make up an Experiment Secret (ES), this is some random string that you store with the experiment. Keep it secret for your participants.

* Make up an Experiment Secret (ES), this is some random string that you store with the experiment. Keep it secret from your participants.

* Store an anonymous Participant Number (PPN) with the data that is related to a certain participant. This participant number can for instance be the token that you use in Limesurvey. It must be unique to the participant and it must not contain information that you cannot give to the participant. It is ok if the PPN is just the participant serial number (1, 2, 3, ...)

* Store an anonymous Participant Number (PPN) with the data that is related to a certain participant. This participant number can for instance be the token that you use in Limesurvey. It must be unique to the participant and it must not contain information that you cannot give to the participant. It is ok if the PPN is just the participant serial number (1, 2, 3, ...)

* Calculate a Participant Identification Code (PIC) checksum for each participant. If you give the participant your contact information, the name of the experiment, the PPN and their PIC, they will be able to prove that they participated in your experiment and you can identify the data that they supplied. Especially if your PPN has a fixed length you can give them a concatenation of PPN and PIC. If for instance the PPN is 1234 and the PIC is A3D4 then you simple send them the following text:

* Calculate a Participant Identification Code (PIC) checksum for each participant. If you give the participant your contact information, the name of the experiment, the PPN and their PIC, they will be able to prove that they participated in your experiment and you can identify the data that they supplied. Especially if your PPN has a fixed length you can give them a concatenation of PPN and PIC. If for instance the PPN is 1234 and the PIC is A3D4 then you simple send them the following text: