Hello, I am applying to:
St. Paul’s School
St. Mark’s
Middlesex
Groton
Andover
Exeter
Some of the schools asked me what other schools I was applying to and how the school ranks in comparison to the other schools. Why is this? Will my honest answer affect my chances?
OP - did they ask you this during your interview or somewhere in writing? There have been other threads discussing this question, as we have been asked this during interviews. Here are some possible answers…
One AO, for example, wanted to know if we were applying to “similar” schools in academics, sports, and (of course) mean SSAT scores. Also, someone told us that they wanted to know for sports - meaning what other teams we were looking at, or would we potentially be playing for - like in the same league. A friend’s son who plays hockey was asked about this during his interviews. He told them something like, “do you want me to play for you or against you?”…You may get a question about your list and rankings from an AO at a same-sex school. If you tell the AO, for example, “ I want to go to an all XY or XX school because being at this type of school offers…” but then you list a bunch of co-ed schools, it could be a red flag. It kind of feels uncomfortable, but be prepared for it!
It also could be asked by an AO who is simply bored, or asking just out of curious its - perhaps, what schools seem to be most popular with applicants this year? I get asked all the time to rank golf courses :))
@Golfgr8: Pine Valley vs. Augusta? Pebble Beach vs. Bayonet (Fort Ord)? 
@The OP: For starters, I think AOs want to see if there is a common theme to the schools you are applying to. Even if that common theme is “prestige” or size. Additionally, I think they ask where they rank with an eye toward yield (the % of people who accept their offers of admission).
My advice: If the school in question is NOT in top 3, then be non-committal but have an answer. Something like a “Well, they’re all great schools, and each one offers something different. I can’t really say at the moment that one is more appealing than the other.” sort of response.
If the school in question is top 3 (or top 1), then by all means say so. The school care very much about yield.
Agree with @SevenDad on advice to OP. My kid was afraid, after being asked a similar question like the one to OP, that the schools AOs would actually talk to each other about applicants (“Mom, do they talk to each other?”).
@SevenDad - Pine Valley, of course! Bayonet or Cypress Point? Whistling Straits? The point or “pointe” is this: It’s like boarding schools - sometimes, the less well known and the less obvious ones are actually the most spectacular - either to just view, to work at, or (if you are fortunate) to experience. My course is #75, yet a true hidden gem. Also, there is a best fit or “right fit” even in golf - know your game and know what you like - don’t just go for a name.
:-B
and skiing 
Anyway, back to the question, I’ve stated this before, but it’s worth a repeat:
For me, my interviews were all well before the application date, so my answer was, “I’m still finalizing the list, but the schools to which I will apply offer X, Y, and Z.”
When I went through the college admissions process my answer before the application deadline was as above. My answer after the application was submitted is, “I’m applying to schools that offer X, Y, and Z, such as AA, AB, and AC,” where two of the schools are at the same level as the school asking the question, and the third is a step below. I would not list all the schools, and I would list them in random (or alphabetical) order. Since some schools ask this question to predict yield, you do not want to reveal to a school that it is your safety (if it is in fact a safety, which in the case of schools like Andover or Exeter, is a safety for nobody).
THANKs guys