Not to sound like I'm arguing both sides, but "not 100%" isn't a real useful basis for evaluation. What happens before or after the 1st day of 1st grade may be important, but 1st grade, and often Kindergarden, is the first crack at teaching kids that the public education system has. Having said that, addressing what makes poor kids 3 years behind in reading already when they get to 4th grade with whatever you can do starting in 1st grade should be an urgent priority for public education in every state.