This study examines the impact of increased product quality information on firms' choices of product quality, using the introduction of hygiene grade cards in Los Angeles County restaurants as a case study. The authors find that the grade cards lead to significant increases in restaurant health inspection scores, consumer demand sensitivity to hygiene quality, and a decrease in foodborne illness hospitalizations. They also show that these improvements are not fully explained by consumers substituting from poor hygiene restaurants to good hygiene restaurants, suggesting that the grade cards cause restaurants to improve their hygiene quality. The study analyzes a panel dataset covering 1996 to 1998, including restaurant health inspection scores, quarterly revenue data, and hospitalization rates for food-related and non-food-related digestive disorders. The results indicate that the grade cards cause an average increase in hygiene scores of about 5.3%, with a significant economic incentive effect, and a 20% decrease in foodborne illness hospitalizations. The study also examines the effects of mandatory and voluntary disclosure, finding statistically significant but small differences in the impact on hygiene quality.This study examines the impact of increased product quality information on firms' choices of product quality, using the introduction of hygiene grade cards in Los Angeles County restaurants as a case study. The authors find that the grade cards lead to significant increases in restaurant health inspection scores, consumer demand sensitivity to hygiene quality, and a decrease in foodborne illness hospitalizations. They also show that these improvements are not fully explained by consumers substituting from poor hygiene restaurants to good hygiene restaurants, suggesting that the grade cards cause restaurants to improve their hygiene quality. The study analyzes a panel dataset covering 1996 to 1998, including restaurant health inspection scores, quarterly revenue data, and hospitalization rates for food-related and non-food-related digestive disorders. The results indicate that the grade cards cause an average increase in hygiene scores of about 5.3%, with a significant economic incentive effect, and a 20% decrease in foodborne illness hospitalizations. The study also examines the effects of mandatory and voluntary disclosure, finding statistically significant but small differences in the impact on hygiene quality.