<p>I have a feeling that is because students who consider themselves good enough in chemistry (or enjoy chemistry enough) to take 5.11x are better prepared anyway for orgo than the students who enroll in 3.091 because they either are weaker in chemistry or don’t enjoy the subject.</p>
<p>The statistics that would be interesting to know but are impossible to get are the 5.12 performances of students who took 3.091 for reasons other than disliking chemistry or finding it difficult (such as my abovementioned friend, who took 3.091 only because she thought she was going to be Course 18 at first and therefore didn’t need more advanced chemistry). I suspect such students would fare better in orgo and more comparably to 5.11x students. And maybe taking 3.091 instead of 5.11x solely because you’ve heard such awesome things about the former won’t put you at a disadvantage later in orgo, either.</p>