If your students access the tests/quizzes via a deep link or embed code (proxy, IP, or referring URL authentication), they are logged into a new anonymous session each time they log back into Instruct. Since they do not return to a saved user account each time they access the quizzes, they can take the same test/quiz multiple times (for example, if it's been assigned in more than one course, or if the instructor has allowed a re-take). If a student has taken a quiz multiple times, all of their scores will appear in the grade report, so instructors can choose to count whichever score is appropriate.
If your students access the tests/quizzes via LTI, their score is linked to their student email address in our system and their grade is passed back to the course gradebook in your LMS. If the student needs to re-take the assessment, for example in another course, their previous answers must be cleared from Credo's system to allow them to submit new answers. Credo's support team can reset student progress entirely (all assessments) or for individual assessments as needed. Just contact us at email@example.com and let us know the student email address(es) and the assessment(s) that need to be reset.