The $4,000 voucher offered by California's Proposition 38 won't spur the creation of new private schools, won't lead existing private schools to expand, and won't open new alternatives to poor and working-class parents who want to leave unsatisfactory public schools. Instead it will primarily subsidize the affluent who already use private schools.

http://epsl.asu.edu/epru/point_of_view_essays/cerai-00-27.htm