Yes, but in studies related to heart transplants, they generally inform you of the pertinent details such as the fact that it is only being conducted on those who successfully underwent surgery and walked away. Later some die, and some live. But the scope of the survey is known and explained. Also, the statistics are readily available because generally there is a great deal of follow-up after these surgeries for years to come as the transplant itself doesn't mean the person is out of the woods.
Whereas with Aspen and other programs, they hire people affiliated with the industry to conduct specific studies, clearly limited in scope in order to portray a false success rate. They could do a survey telling how many prisoners complete their first week and it would amount to about the same thing.
The number of kids who complete the program is of no value since it is basically a teenage prison camp. The teens are not allowed to leave without parental permission, running away or breaking the law. No different than real prison really, except you would exchange parental permission for court permission. That kids are forced to stay there for the entire duration of the program is therefore a useless source of data to base a survey on. Unless you have solid, long term data ranging in to multiple years, preferably at least ten, to determine the value of the program well after it is completed, the survey would have limited value.
I just got in to contact with my former "older brother" from my old program. In a brief email, he rattled off about twenty five students who there while I was there, and nearly every single one of them had run in to problems ranging from going back to drug use, alcoholism, problems with their parents, suicide. The same reasons and more that they went in to the program to begin with. These are people who are now in their forties, some almost fifty. So more than a quarter century after attending a program, run by the same people who founded Aspen and Monarch, these former teen prisoners are not all faring well. Many eventually came around and made something more of their lives, but the bulk had not, and those that had took at least fifteen years. So add that to your survey!