Consumer Information, Product Quality, and Seller Reputation by Carl Shapiro is a doctoral thesis exploring how markets function when buyers cannot observe product quality before purchase. The thesis argues that while reputations can help maintain quality, they are not perfect. Sellers may still cut quality without detection, reducing incentives to maintain high standards. The thesis analyzes a monopoly seller in an environment of imperfect information, showing that self-fulfilling quality levels are lower than those under perfect information. It also examines a perfectly competitive environment where reputations play a key role, leading to higher prices for high-quality products despite competition. The analysis highlights welfare losses due to imperfect information and explores the effects of consumer information remedies. The thesis also discusses minimum quality standards and their benefits for consumers who prefer high-quality products. It concludes that raising minimum quality standards can exclude some products from the market, even though they may be desired by some consumers. The thesis is supported by various economic theories and models, including the analysis of consumer learning, the role of reputation, and the impact of imperfect information on market outcomes. It also considers the effects of advertising, warranties, and other information provision strategies on consumer behavior and market performance. The thesis concludes that while imperfect information can lead to market inefficiencies, it can also provide welfare benefits in a second-best world.Consumer Information, Product Quality, and Seller Reputation by Carl Shapiro is a doctoral thesis exploring how markets function when buyers cannot observe product quality before purchase. The thesis argues that while reputations can help maintain quality, they are not perfect. Sellers may still cut quality without detection, reducing incentives to maintain high standards. The thesis analyzes a monopoly seller in an environment of imperfect information, showing that self-fulfilling quality levels are lower than those under perfect information. It also examines a perfectly competitive environment where reputations play a key role, leading to higher prices for high-quality products despite competition. The analysis highlights welfare losses due to imperfect information and explores the effects of consumer information remedies. The thesis also discusses minimum quality standards and their benefits for consumers who prefer high-quality products. It concludes that raising minimum quality standards can exclude some products from the market, even though they may be desired by some consumers. The thesis is supported by various economic theories and models, including the analysis of consumer learning, the role of reputation, and the impact of imperfect information on market outcomes. It also considers the effects of advertising, warranties, and other information provision strategies on consumer behavior and market performance. The thesis concludes that while imperfect information can lead to market inefficiencies, it can also provide welfare benefits in a second-best world.