In a section card The bar charts display a varying number of bars as I move between assignments, some have 13 bars, some have 21. This is odd.
It seems that there are N bars of equal width, plus one bar for "100%". Again, odd.
Hovering over a single bar displays the range of grades represented by the bar. However, it seems that the bounds are listed as the actual upper and lower bounds of the recorded data points, not the bounds of the region. This gives the impression that the bounds of are not equal-width, even though the bars are drawn as equal width.
Distribution curves are not rendered when all students receive 100%, or 0%, likely because the curve would be useless. However really, really, bad curves are drawn when the data is bimodal (half 0%, half 100%, for example). From my small sample set, it looks to me this is always rendering a gaussian distribution. If I'm correct, That's a bad distribution assumption to make. Many assessments will be bimodal, or have other (non-gaussian) distributions.
When looking at the average, high, and low grades in the card, some of my assignments list "-0.0%" as the low grade. Some bounds-checking needs to be fixed.
When viewing a Student Card, it would be informative to see the students grade in relation to the distribution of their peers, for example, by highlighting their position within the bar chart shown on course or section card.