Anonymous Participant IDs
If you would like to match participant data across multiple sessions, but do not want to break anonymity by storing a lookup table of email address to participant ID, feel free to use my VESPR Anonymous Participant IDs tool.
To use it, you would need to send your participants to the site and ask them to enter their email address and request an ID. Their address is converted into a number which is then emailed to them for use in your study. This method does, of course, rely on your participants remembering which email address they used if they go back to the site rather than checking their emails for the follow-up time points.
My site does not keep a record of what email addresses have requested IDs and it would be impossible to convert the ID number back into an email address. In theory there is a small risk that two participants could be allocated the same ID but the algorithm makes this very unlikely.
Please cite this reference if you use the tool in your research.
Morys-Carter, W.L. (2021, November 2). Anonymous participant IDs . VESPR. https://moryscarter.com/vespr/id.php.