Sometimes it is out of the teachers hands. I am a second year teacher and because of this in my province my students need to take the provincial exam. I personally gave a girl a 30% in the class, the test was worth 40% of her final mark. I found out just the other day that she ended up with a 51%. While talking to the principal about the whole thing he mentioned that every kid should try the class because then they at least have a shot at it and just may get it "whether the mark is legit or not". And that is where the frustration is for me because as a teacher its damn near impossible to fail a child now. The rumour on the street (well the teaching street) is that marks as low as 42% are now being rounded up to a 50%.
A friend of mine once said, "When a child is born we should hand them their birth certificate and their high school diploma because thats what education is turning into."