Take a look at PISA results (just an example of formal evaluation of teens abilities): http://news.ycombinator.com/item?id=245192 http://news.ycombinator.com/it

Take a look at PISA results (just an example of formal evaluation of teens abilities): http://news.ycombinator.com/item?id=245192 http://news.ycombinator.com/item?id=245192 http://news.ycombinator.com/item?id=257836 http://news.ycombinator.com/item?id=257836