<p>My perspective is based on highly anecdotal data. I know (or know of) many undergrad students in science and engg programs at top schools, and several grad students in the same programs. I felt the latter (barring a couple who were spectacular) weren't of the same caliber as those in the first group. Is it just that I have a misguided view, or is it really true that the average or median student in the graduate programs wouldn't have been accepted as an undergrad, but did so subsequently because the pool is less competitive, with the high fliers having gone to industry?</p>
<p>Maybe your sample size isn’t really adequate? I am also thinking that sometimes undergrad doesn’t separate the men from the boys, as it were.</p>
<p>My experience with first-year grad students working as TA’s in my chem lab has been the opposite of your anecdotal data. In almost all cases, the students who come to grad school have been much stronger than the average graduating undergrad. I can’t say about engineering, but in the sciences where bachelor’s level jobs generally aren’t very attractive, the high fliers tend to go on to further schooling – law, pharmacy, business, medicine, graduate, etc.</p>