<p>What Uroogla said is generally true of subject-specific grad schools (i.e., PhD programs). Professional schools are a very different beast, and have been discussed elsewhere here. For example, there's pretty good reason to think that law schools don't give a damn what you take S/NC.</p>
<p>The S/NC cut-off was moved earlier during my time at Brown, to help prevent people from gaming the system. I think that the administration is sometimes a bit too worried about gamesmanship, and that the faculty is sometimes a little too quick to unilaterally fiddle with a curriculum that was the result of a mutual agreement among students and faculty. So far as I'm concerned, to the extent that people are doing things like dropping classes to avoid a B, Brown's admitting people that it shouldn't be.</p>
<p>A note to high-schoolers that's relevant to this thread: In college, at least at a place like Brown, grading is the prerogative of individual professors. Professors don't report your progress through the course to the school; they're not required to follow specific grading guidelines; they don't follow any one system for grading. At the end of the semester, the professor simply reports your letter grade or S (or NC), and that's it. It's generally just a magical black box. You're best off disavowing yourself right now of any notion that grading (except in a couple of departments) will follow some kind of consistent or describable pattern. Students' obsession with the security blanket of knowing 'how they're going to be graded' cause professors to make ridiculous claims like "participation will count for 25% of your grade." There are too many degrees of freedom for that to make any meaningful sense. Just do a good job and you'll have a good shot at getting an A or S-HD.</p>