<p>There are a wide variety of reasons for this, some good, some bad, some that just are.</p>
<p>One set of reasons is obviously financial. MIT receives quite a bit of money from the US government for a variety of purposes and is definitely an American university. MIT would definitely not want it to be perceived as anything else. </p>
<p>Tied in with that is that MIT always admits need-blind. The role of the admissions office is to pick the 1600 top students of all that applied, without regard to their ability to pay. The role of the Financial Aid office is to ensure that every single student that the admissions office has chosen as "someone we want" can afford to go to MIT. Not that it will necessarily be easy to pay, or that paying the bill won't hurt. But the office will ensure that the admitted students are capable of attending MIT. As an American university, there are a wide variety of governmental and other funding sources that are available to provide financial aid to Americans. These options are largely unavailable to international students, whose aid must come from the Institute general funds.</p>
<p>There are several other reasons as well. The end result is that the MIT administration has placed a quota requirement on the admissions office. The admissions office can admit currently about 5% of international applicants.</p>
<p>That alone would make the international applicant pool highly competitive. To make matters worse, the international pool is often more highly self selective than the domestic pool. In the American applicants is is not uncommon to apply to at least one school that you know is likely to be a bit of a stretch. You apply to Harvard, Princeton, MIT, or some other top school despite your 530 verbal 590 math SAT scores and a high school transcript filled mainly with C's. These are the easy decisions and tend to inflate the difficulty of entry into top American Universities. </p>
<p>By contrast, most international applicants apply to ambitious schools only in their own region. That is they might apply to Oxford or Cambridge or the Indian Institutes of Technology, even if they think it might be a stretch to get in, but they rarely apply to MIT on a whim.</p>
<p>Those international candidates applying from outside North America, tend to only apply if they think they can get in. The process can be very different from what they are used to. They may well have to fly somewhere in order to sit the SATs (for example the only SAT administration in Africa is in Kenya, I believe). It really is non trivial to apply to an American institution for a non-American. As a result, not only is the admissions rate capped, but the international pool tends to be made up of some of the most motivated and impressive candidates overall.</p>
<p>MIT undergraduate admissions remains highly competitive for international students and it will remain so for the foreseeable future.</p>
<p>-Mikalye</p>
<p>PS: Remember that MIT classifies applications by Citizenship, not by residence. If you are a US citizen or a holder of US permanent residence (green card) status then you apply as an American. Otherwise, you are an international student. I'm a European EC, and every year I get several Americans applying to MIT from Europe.</p>