At clinicaltrials.gov you can look up studies to learn more about them. On one such study, I saw this block of text:
Study Type: Interventional Study Design: Allocation: Randomized Intervention Model: Parallel Assignment Masking: Participant, Care Provider, Investigator, Outcomes Assessor Primary Purpose: Treatment
I understand all of these except the last one. To the untrained eye, that sounds like "we mostly want to treat people, but we will gather data while we're doing so." Is that a correct interpretation? What are other possible responses to "Primary Purpose" and how would they differ from "Treatment"?