My brand-new course got a second review, and I got surprised with that. It was someone who finished 2% of my course. She didn´t give a bad grade to my course, that´s not the problem, but... is it possible to evaluate a course after following 2% of it?!
I think it should be mandatory to reach, let´s say, 70% of a course to be allowed to review it.
When our product team was studying this issue, they found that there is about a 10 minute period to hook a student and convince them to continue on with a course. To this end, it's useful feedback to find out whether or not the beginning of a course is resonating with students.
This helps give a more complete representation of student satisfaction in a course because only students who like a course will complete 30%, 40%, 50%, and onward, while students who aren't satisfied with a course will drop out before that time.
Students always have the option to update their reviews and will continue to be prompted to do so. In our testing of this feature, students who left reviews at an early prompt were likely to keep updating their reviews when further prompted.
I appreciate your concern about this and I've passed this feedback on to our product team. Please let me know if I can provide any additional help or clarification on this.