First, make sure that you're working on the professional server s2survey.net and that you have prepared the DPA (see Personal Data) as your data will definitely be person-related data, and therefore is subject to the GDPR.
I would then recommend the following procedure:
- Create a table with the email addresses, maybe gender and names (for personalized emails) and the patient ID as a separate table.
- Save the table as CSV and import the address list into SoSci Survey. Map the patient ID column to the "Custom 1" attribute.
- Create an internal variable in SoSci Survey, for example IV01_01
- Put these lines of PHP code below on the first page (or anywhere else) of your questionnaire to write the ID from the address list into the questionnaire.
- Send the mailings via SoSci Survey, using personalized URLs (which is the default option).
$data = panelData();