In a perfect world, your numbers year to year should be pretty consistent, which will put them at ease. Unfortunately, that’s rarely the case with 1099 contractors (especially artists, songwriters, etc.). There’s great years, good years, and bad years. That’s just the way it is.
A lot of the time, the student has no particular goal beyond “do this assignment.” So then the critique needs to get creative. I like to ask: If this track is a film or game score, what’s happening in the scene? Students have a lot of implicit knowledge in this area from their own media consumption, so I get wonderfully specific and unexpected answers to this, i.e., “It’s a bar fight in a domed underwater city.” Then we can figure out, how could the track more strongly convey the feeling of a bar fight in a domed underwater city?