Kindergarten is more academic than it used to be. Kids are expected to learn to read. They are expected to know how to behave in school already. Not all five year olds are ready for this. Individual parents have to do what's best for their kids. This may reinforce the pressures for academic kindergarten, but a parent who tries to buck the system may hurt their child.

I don't think red-shirting is the cause of the change in kindergarten as much as the change has caused more red-shirting. The increased academics in kindergarten could also be because more children have been to pre-school before kindergarten and have learned the alphabet. In addition, educators are under pressure to raise test scores now or lose their jobs.

The No Child Left Behind Act rewards immediate increases in test scores and doesn't measure whether or not individual children learn more by the time they are 17. If children are older in kindergarten and learn to read before 1st grade, test scores of 3rd graders will go up without schools having to improve their teaching methods. The increases may disappear by the time the children are 17 - or they may not if the curriculum gets harder at each grade level.