In Austria, my children were given three years of cost-free half-day kindergarten. (The teachers were extremely well prepared. It was amazing, wonderful and worth every cent the Austrian people spent on those three years.)
After their three years of (cost-free, half-day) kindergarten, my children were required to be six years old and to take a TEST, yes, a TEST before they could enter the first grade. The test required them to draw a picture. Those who could not draw a picture were deemed to lack the mental maturity and skills to enter the first grade. They had to wait.
If we tested children in this simple way before allowing them to start the first grade, we would have better results in the twelfth grade. That is because it is the children who start first grade without the dexterity, skills and maturity to learn to read, write and calculate who slow down the whole process. Experts can determine whether a child has certain minimal cognitive readiness from a picture.
Testing children before putting them on a failure track would save taxpayers a lot of money and families a lot of heartbreak.