Basically: they have prerequisites for parental involvement (i.e. your parents have to be willing to work at your schooling too), and a high attrition rate (i.e. they throw out the underperformers). That's not a random sample, it's self-selected for people who do well in it.
This doesn't mean that it's a bad idea, or that it doesn't work. But it means you have to be very careful about pronouncing it "working well."
http://en.wikipedia.org/wiki/Knowledge_Is_Power_Program#Crit...
Basically: they have prerequisites for parental involvement (i.e. your parents have to be willing to work at your schooling too), and a high attrition rate (i.e. they throw out the underperformers). That's not a random sample, it's self-selected for people who do well in it.
This doesn't mean that it's a bad idea, or that it doesn't work. But it means you have to be very careful about pronouncing it "working well."