Hi, I am carrying out a study using the Delphi method. For this, we will be sending out an initial questionnaire to participants, then after analysing the responses from this questionnaire, sending out a second questionnaire. The second round questionnaire will be based on the findings from the round one questionnaire. We may also create a third round questionnaire. For this, I will need to generate a unique ID number for participants, and then have this same unique ID number linked to the participant in each round so that if the participant asks for their data to be withdrawn, we can withdraw all of their data (the study will be anonymous).
I have read this tutorial: https://www.qualtrics.com/support/survey-platform/common-use-cases-rc/pulling-data-into-a-second-survey-longitudinal-surveys/, and can see it is possible to pull unique ID numbers into a second survey, however in our case, we may have some participants that complete the round 2 questionnaire without completing the round 1 questionnaire. I am wondering if it is possible to pull unique ID numbers into the second round where the participant has completed round 1, and create a unique ID number in the round 2 questionnaire for those that have not participated in the round 1. Any help or advice on this would be much appreciated.