Though I agree working with the parents rather than children is key, is focus on parental income really your intention? (investinginkids.net)
The court will then consider the percentage each parent contributes to this combined parental income to determine each parent's support obligation. (info.legalzoom.com)
This allows them to measure family characteristics (such as parental income) not typically controlled for when teacher value - added is estimated. (educationnext.org)