Over 20 years after the initial study, researchers still find that parents in Arizona have the most freedom in choosing what education is best for their children, compared to parents in the rest of the United States. In 2000, the pro-school choice think tank Manhattan Institute created the Educational Freedom Index (EFI) to measure how much educational freedom parents in each of 50 U.S. states possessed at that time. Specifically, the EFI judges each state based on various factors, such as whether parents have a wide selection of charter schools from which to choose, whether parents have access to private school options via vouchers or tax subsidies, whether parents can home school their children with relatively few restrictions, and whether school districts are small enough to make it easy for parents to transfer their children from one to another without having to move. Arizona, which was undergoing a rapid expansion …