Ching-to Albert Ma and Henry Y. Mak
A monopolist produces a good with two qualities. All consumers have the same valuation of the first quality, but their valuations of the second vary, and are their private information. A public agency can verify qualities, and make credible reports to consumers. In Full Quality Report, the public agency reports both qualities. In Average Quality Report, it reports a weighted average of qualities. The equilibrium prices and qualities in Full Quality Report can be implemented by Average Quality Report. Equilibrium prices and qualities in Average Quality Report give higher consumer surplus than Full Quality Report. Bertrand competition under Average Quality Report yields first-best prices and qualities.