It's basic economics: prices provide valuable information and price ceilings cause shortages. (educationnext.org)
However, particularly if the voucher value is relatively small, price ceilings mean that private schools will likely only fill empty seats rather than expand enrollment. (educationnext.org)
The book business is not quite so price - fixed, but traditional price ceilings govern the market. (theworldsgreatestbook.com)