Solved
Prevent the same email from taking a survey more than once from different devices
If I use the Prevent Ballot Box Stuffing that only prevents a user from re-taking the survey from the same machine. How can I prevent them taking the same survey from a different device?
Best answer by TomG
If you aren't using a Contact List, there really isn't an easy way.
If you can't use a Contact List, you could create a web service to store email addresses externally. Then create another web service to check an entered email address against the stored addresses and terminate the survey if the email address is already stored.
+27If you aren't using a Contact List, there really isn't an easy way.
If you can't use a Contact List, you could create a web service to store email addresses externally. Then create another web service to check an entered email address against the stored addresses and terminate the survey if the email address is already stored.
+23Talking about this, Have you guys tried Fraud detection?
We were thinking to test drive it, but ended up using the contact list to be sure-sure.
@TomG do you have any experience with this option?
I totally agree with what @TomG said, but just backing it up a step for you: the only way to prevent this within Qualtrics is to use unique URLs, either via email distribution or unique URLs. If you are using an anonymous link, you will be unable to prevent someone from taking it on multiple devices.
You _could_ collect their email, then use the contact list trigger to store that information. That would allow you to de-dupe after the survey closes.
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