<p>It depends on the university, the department, and the courses themselves. Sometimes the material is shuffled and distributed across different courses, so it boils down to the same material of 2 semesters spread across 3 quarters. Other times the material of 1 semester class is squeezed into 1 quarter, meaning the class moves faster and requires you to master the material at a quicker pace, so you actually end up learning more in a 3-quarter period. Still other times they do a combination of the two–shuffling some material while cramming more material into 10 weeks than what you’d cover in the first 10 weeks of a semester. </p>
<p>At Stanford, for example, this condensing of material tends to be the case: the classes move more quickly, forcing you to stay focused hard on the material to get it down in time, without compromising the depth of study required for the material. This is how some top schools like Stanford mitigate the rampant grade inflation that comes with higher selectivity: keep the students on their toes by making the class structure harder, the material rigorous, and (in the end) the grades high.</p>
<p>Often on the quarter system, material “overflow” can be pushed to the sections/discussions, projects/papers/assignments, and independent study. That’s why office hours for both professors and TAs tend to be very important as well. These out-of-class avenues also allow students to interact with the material enough so that it doesn’t seem as though they’re just rushing through. Inevitably, though, the quarter system will feel very fast and each term is over before you know it.</p>
<p>But IMO this is why the quarter system is better than the semester system: you take more classes, you often learn more, and you’re kept on your toes to get the depth of the material at a quicker pace.</p>
<p>(For the record, I don’t think this is how it is at most quarter system schools. This increase in intensity is true only if they think the students can handle it, which tends to be the case at more selective schools.)</p>