Can you restrict multiple entries using anonymous survey link

@nicoleh15 For anonymous surveys the prevent multiple submissions setting is cookie-based which means that once the browser cookies are deleted by the participant, it would be possible to take the survey again. 

As alternative, check my description here. 

• Create an empty mailing list at first.
• You need a question to ask for the email address at the start of your survey.
• Add a contact list trigger to your survey to add the email addresses to the mailing list.
• Add an authenticator element to your survey flow which is prefilled with the email address entered in the question. Authenticate using the contact list you created earlier. “Maximum authentication attempts” of the authenticator should be set to 1. Make sure to check “Allow authenticating users to retake authenticated section” within the authenticator options. Within the authenticator branch, create an end of survey which does not record the response and says something like “Sorry, but you already participated.”. After then authenticator element, place your actual questions.

At the end, it should somehow look like this.

Best
Christian

Has anyone explored alternative method in the case we do not incorporate any PI questions in the survey?

Can you use a case ID number or External Reference Number as the identifier in this case? Can you create a list off of this data instead of the email address?