I'm just going to focus on mathematics since that is what I know. I really don't know what an AP class in any other subject would look like. I teach a Calculus 1 class every fall. I ask every semester how many had taken AP calculus in HS. A vast majority respond that they had. so...the semester starts and I find out very quickly (every semester) that 1) many of the students know very little trigonometry 2) their algebra skills are very weak. 3) they don't remember how to take a limit. 4) they DO know how to take a derivative (for the most part) using the formulas (product rule, quotient rule, ect), but if you ask them to take the derivative using the definition of a derivative most of them have a difficult time. some can't even tell me what f(x+h) is if I give them a simple function. ex. f(x)=x^2+x+1 then f(x+h)=(x+h)^2+x+h+1 Wouldn't it be better for most student to master algebra/trig before they take on calculus? I extend this to all subjects. Are we helping or hurting students by offering AP classes in HS?