Pulling a handfull of fourth graders from one of the worst education districts in the U.S. and comparing them to peers from another countries elite is hardly scientific and totally distorting.
Yeah, its hard to make direct comparisons. Nobody is born knowledgeable, nature provides very little, its the nurture thereafter that really makes a individual shine, and a gifted person blossom. Unfortunately for a lot of the public schools in most states, the children there doesn't have any opportunities to be nurtured properly because they are under challenged. Here in the North America, we hardly took a look at how everyone else in the world is commencing their elementary school programs, we've always just assumed that because we are powerful and wealthy, we should automatically get everything right on the first try. This obviously didn't work for public education. There is a huge gap between the "smart" and the "street smart", and the number of victims falling into the latter has dramatically increased overtime. We can push our students a bit harder, not to the extremes of China and Japan, or even India, but it might be too late to not work our kids.
Its not entirely the education systems' fault, I mind you, since all that attention they've been lavishing on video games, self-images and peer-pressure really doesn't help either.