<p>1&3. I’m taking five classes right now. My two intro classes are large lectures: one with about 150 people and no discussion section, and one with about 60 people and a weekly discussion section led by a TA. Then I have an introductory language class with about 14 people, UWriting with about 14 people, and Lit Hum with about 22. Lit Hum and UWriting are discussion based; the language class is more lecturish. </p>
<p>Teaching Assistants (usually grad students or advanced undergraduates) assist the instructor or professor and occasionally lead discussion sections, but by definition are not instructors themselves. Sometimes, however, graduate students can be instructors. My Lit Hum and UWriting instructors are both grad students.</p>
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<li>It varies. They all hold office hours, but some really make an effort to appear accessible and others don’t so much. My two grad student instructors are actually the best about being approachable, probably because 1) they aren’t too busy with their own research to deal with undergraduates and 2) they are eager to avoid the stereotype grad students have as been disinterested and incompetent. Columbia has tons of grad students, and if one has been selected to teach you it means that he or she is one of the best. Theoretically, at least. So far it’s worked out well for me.</li>
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<p>Also: Classics here is GREAT. My experience with the professors and the department has been nothing but amazing so far (:</p>
<p>As far as campus community, it does take a certain amount of initiative to get involved in things. This is a huge, busy, fast-moving place, and no one is going to check up on you. I actually haven’t found that the city saps campus social life, just that it can be easy to isolate yourself from the community socially because of work, stress, laziness, etc. If you don’t make the effort be get involved, its easy to get lost in the shuffle.</p>