We're currently setting up a randomised controlled study using Qualtrics , for which we're struggling on assigning a unique intervention or control link/code to a user at the end of the study.
Flow: We want to ask questions, and at the end randomly assign users to either intervention or control group, and show them a unique code based on the assigned group.
Our struggles:
a) How do we randomise one of the two in a way that the user gets only one of the code displayed on the final screen and the email sent?
b) These unique links will be pre-loaded. How can we ensure that the same one does not get assigned to multiple users? Is there a way to track this or any kind of safeguard?
