Val, as always, has written a thoughtful response. I want to focus on a couple of parts of this:
Honestly, I think that the highly selective colleges want what they want, and they dress that idea up to make it politically palatable while doing what they like behind the scenes. This is my way of saying that I think the whole process is a farce. Following from that idea, I see little value in discussing "what colleges want" without acknowledging that admissions practices may be very different when the wind changes direction in 18 months. Not to mention how toxic they are.
Yes, it can become toxic. We consciously try to avoid that by having our kids do what they want rather than forcing activities that others think might look good. But this is worthy of its own topic.
A case in point is that admissions committees look for "research scientists" in the applicant pool. There is no such thing as a 17-year-old research scientist unless s/he has already finished a postdoc (in which case, there's no need to apply to Yale undergrad). But we have a fantasy that the Intel science competition turns kids into researchers. It doesn't. It's just a start on a long road.
This is completely true. However, I think the admissions people are just looking for potential in this area and in other areas. The research that a gifted 17-year old can perform won't be the same as what he/she can do several years later, in the same way that a talented high school athlete won't have the same skills that a 25 year old does. But in both cases, the potential can be seen.
