The Common Core State Standards website asks,
Q: Why do we need educational standards?
A: We need standards to ensure that all students, no matter where they live, are prepared for success in postsecondary education and the workforce.
Let’s assume for a moment that that is the goal of primary and secondary education. (Let’s also ignore the missing hyphen between post and secondary.) Will full-day Kindergarten help in achieving this goal?
No.
Why not?
Because extreme differences in academic ability collapse by the fourth grade. All of us, including children, learn at different rates. In general, those differences disappear on average by the time we are about ten years old, or fourth grade. I understand the difficulty of scientific experiments on humans, but we do what we can; and what we can do shows that there’s no evidence that learning a subject earlier makes a difference.
So, what exactly is the point of full-day Kindergarten?