government subsidy
The government issues school vouchers to parents, and the amount is equal to the amount that the government subsidizes individual students every year.
free choice
Parents are free to choose schools that meet the prescribed requirements, whether public or private.
Free market mechanism
Parents use school vouchers to pay tuition fees, and schools have the right to charge extra fees other than school vouchers, which is determined by the free market mechanism.
Teachers' union dispute
Teachers' union believes that this system threatens teachers' professional stability. Therefore, when many states in the United States implemented the voucher system, it triggered some kind of legal proceedings between the trade unions and the government.