A little old data, but still relevant.
S & M had lots of kids in engineering front, so their feeder rates to B, L, M schools are lower
5 LACs made the top 15 - Williams, Amherst, Swarthmore, Pomona, Wellesley. These 5 have constantly been ranked in top LAC list on US News. - everything is consistent and makes sense here.
http://www.inside-higher-ed.com/wp-content/uploads/2013/04/wsj_college_092503.pdf