Before revision:  A novel feature of our tools is that they allow specifying the relationship of the demand for the various schoolswith respect to pricesto be entirely nonparametric or to be parameterized in a flexible manner, both of which do not necessarily imply that the welfare parameters are point identified.
After revision:  A novel feature of our tools is that they allow specifying the relationship of the demand for the different schools. However, while the random allocation of the voucher reveals the value of demand at two prices, the parameters generally depend on their values beyond these prices. Our tools show how to sharply characterize what we can learn when demand is allowed to remain entirely nonparametric or to be parameterized in a flexible manner, both of which do not necessarily imply that the welfare parameters are point identified.