Hello,
Our non-profit is designing a longitudinal study over a 3 month period where participants in an online course will essentially answer the same survey questions at the beginning, middle, and end of the course.
We are asking for name/email/phone on the first response, and then using their email/phone to ID them for the second two responses (via Authenticator in the survey flow).
We are using 1 survey project and using a qualifying question at the beginning (ie 'is your course beginning or ending?') to flag the responses for their different phases of the project. I have some questions:

1. Is it the right approach to use one survey project, or should we be using a different survey for each phase (beginning/middle/end)?


2. When we look at aggregated survey results at the end, we want to be able to filter out people that did not complete the course and therefore all three survey responses. Is this something we can do easily? We worked with an external developer in the past on a similar project, and they had do do something via API to mark the responses as 'matched' when a person complete all three, but I am wondering if there's an easier way?