<p>I expect that what charlieschm is referring to, is summer programs that are invitation-only for selected, highly desired students who are weak in one area or another. My alma mater used to run (and may still for all I know) a summer program for certain students that it wanted who weren’t quite up to snuff in X, Y, or Z because of limitations in their high school environments. One good friend who was invited had come from a microscopic rural school district in the Northern Plains where students there were only about 25 students in the whole high school.</p>