MIT PRIMES certainly serves as a useful pipeline, but I am talking about something else. My son was in MIT PRIMES, and was accepted to MIT (he chose Harvard instead). Most MIT PRIMES students get accepted to MIT, but our observation is that about 25% do not.

But "invited to apply" is an entirely different category that is reserved for US applicants that have proven they are world-class in math and physics, and to a lesser extent in Chemistry.