One argument for Small Area Fair Market Rents (SAFMRs) is that they would reduce overpayment for voucher units in low-rent neighborhoods. This leads to the belief that the benefits of SAFMRs can be funded largely by reductions in landlord profits rather than by losses to voucher recipients who remain in low-rent areas. The usual theoretical argument that has led many to believe that voucher units are overpriced focuses on one implication of one feature of the Housing Choice Voucher program. This article provides a more comprehensive theoretical analysis that leads to the conclusion that the worst voucher units and those in the worst neighborhoods will usually rent for more than the mean market rent of identical units, and the best units in the best neighborhoods will rent for less than this amount. The debate over this matter has ignored the bulk of the available evidence. This article summarizes and assesses the data, methods, and results of the major studies. The evidence is consistent with the general pattern predicted by the comprehensive theoretical analysis but also with an alternative explanation that challenges its interpretation of overpayments and underpayments for voucher units. The mix of units with estimated overpayments and underpayments varies across studies, but the weight of the evidence is that the aggregate differences are modest. Finally, the evidence available indicates that SAFMRs will decrease the rents paid for voucher units with any specified set of characteristics in the worst neighborhoods and will increase the rents of such units in the best neighborhoods.