I think the poor would improve under a voucher system. They are poor because of economics, not poor because they are lacking intelligence.

June 20, 2008
Safer Kids, Better Test Scores: The D.C. Voucher Program Works
by Shanea Watkins, Ph.D.

“Despite this lack of statistical differentiation, students who participated in the Opportunity Scholarship Program achieved higher reading scores than students who did not. The study also indicated that certain subgroups of students experienced significant positive gains in reading achievement.[3] These results are encouraging because they offer compelling evidence of two years of positive achievement gains for D.C. voucher program participants.[4]”