I'm not sure how to read this. I could interpret the bimodal outcome as the initial skill of the student being the main factor. Either you get it, or you don't,

I'm not sure how to read this. I could interpret the bimodal outcome as the initial skill of the student being the main factor. Either you get it, or you don't, and the lecturer had no real influence on the outcome. The reweighting is not a good solution, but I would ask questions to the lecturer why a good chunk of her students are failing. It's her responsibility to teach them after all, and not to filter out the elite.