It depends on where and when you are talking about.

When I was growing up anyone who was nominated by their teachers would simply skip grades or get shifted into an honours program if it was available for their level.

Just as I was graduating high school however, all the gifted programs were phased out as being unnecessary (or unfair depending on whom you talked to). There was much hay made about the tight school budget needing to go to support students who were being left behind by the new national testing standards.

Now, though, ten years later, they have magnet schools for the talented which are by nomination only.