Pay the parents if the kid keeps in school

Likely the best way to do No Child Left Behind.   The second best method is pay the school for attendance, the first has to be pay the parent.

The parent has the most causal effect on school attendance, get the parent incentivized to move the kid and the school, direct payments result in parental involvement.  The parent receives attendance records, and parents specify that the IRS gets a copy from the school board.  Better parents get the bigger check.