<p>First of all, Huntsman is not an International Relations program. It is a dual degree program in Business and International Studies. International Studies is the intensive study of a particular region.
There is a couple of reasons for the popularity of these programs. One is the resources available. Help with job/internship placement, a dedicated lounge and classrooms, etc. Another is the community that is fostered. Many students choose Hunstman over Harvard, Yale, etc. and for a lot of them it is because of the cooperative learning environment, as opposed to a more competitive one. Huntsman students become invested in the collective success of the group, and this is fostered very intentionally (a big part of them all living together the first year).
Acceptance to these programs is far more selective than HYPS, so another benefit is that the students are all with other students who are truly the best of the best. Because so many of them turn down other top programs, they are exactly where they want to be.</p>