<p>
</p>
<p>Such rankings are too generalized to be useful, since the rigor levels may vary across departments. Some schools may have several options for a given course (e.g. regular versus honors courses). A somewhat extreme example of the latter is Harvard’s entry-level math courses, which range from Ma-Mb (sort of like high school calculus AB with precalculus review) to 55a-55b (a famously difficult honors math course). In between are 1a-1b (normal frosh calculus), 21a-21b (normal sophomore math), 23a-23b (honors sophomore math), and 25a-25b (higher honors sophomore math).</p>