I would argue that research into the effectiveness of school choice programs should focus on the supply response of schools, the providers of the education service. Most current voucher programs are limited and they can hardly impact school behaviour. Voucher or lottery winning students simply crowd out other students. Student composition may change, in fact, average test scores for the school may decline, but the private schools accepting voucher/lottery students do not feel much financial pressure due to competition. We need school choice to become a universal phenomenon in some large area. In such an environment, school choice is seen as a real competitive threat to schools' very survival. Of course, in equilibrium, we would end up with little difference in outcomes among public, private, and other types of schools. Every child, no matter what school they attend, would benefit as schools fight for "customers" and the performance of the entire education system improves. Competition can produce miracles if and when allowed to work.