This study examines the effect of increased product quality information on firms' choices of product quality, using the introduction of restaurant hygiene grade cards in Los Angeles County in 1998 as a case study. The grade cards, which display restaurant hygiene inspection scores, led to several significant outcomes: (i) an increase in restaurant health inspection scores, (ii) increased consumer sensitivity to restaurant hygiene quality, and (iii) a decrease in foodborne illness hospitalizations. The study also finds that the improvement in health outcomes is not fully explained by consumers switching from poor hygiene restaurants to good hygiene ones, suggesting that the grade cards actually cause restaurants to improve their hygiene quality. The study uses a panel dataset covering 1996 to 1998, including restaurant inspection scores, quarterly revenue data, and hospital admission data for California. It finds that the introduction of grade cards caused a 5% increase in restaurant revenue for A-grade restaurants compared to B-grade ones, indicating that consumers respond to hygiene quality information. The study also shows that grade cards led to a 20% decrease in foodborne illness hospitalizations, suggesting that the grade cards have a real impact on restaurant hygiene practices. The study also explores the effects of mandatory and voluntary disclosure of hygiene grade cards. While there are statistically significant differences in the effects on hygiene quality, the differences are small in magnitude. This suggests that firms may voluntarily choose to disclose hygiene grade cards, or they may be anticipating a future mandatory disclosure. The study finds that the effects of mandatory and voluntary disclosure are similar, but the magnitude of the difference is small. The study also discusses the potential impacts of information disclosure on firm behavior, including the mitigation of information asymmetry and the effects on competition among restaurants. The study finds that the introduction of grade cards leads to an increase in restaurant hygiene quality and a decrease in food-related illnesses, suggesting that the grade cards do cause restaurants to improve their hygiene practices. The study concludes that the increased provision of product quality information to consumers does lead to an increase in firms' product quality.This study examines the effect of increased product quality information on firms' choices of product quality, using the introduction of restaurant hygiene grade cards in Los Angeles County in 1998 as a case study. The grade cards, which display restaurant hygiene inspection scores, led to several significant outcomes: (i) an increase in restaurant health inspection scores, (ii) increased consumer sensitivity to restaurant hygiene quality, and (iii) a decrease in foodborne illness hospitalizations. The study also finds that the improvement in health outcomes is not fully explained by consumers switching from poor hygiene restaurants to good hygiene ones, suggesting that the grade cards actually cause restaurants to improve their hygiene quality. The study uses a panel dataset covering 1996 to 1998, including restaurant inspection scores, quarterly revenue data, and hospital admission data for California. It finds that the introduction of grade cards caused a 5% increase in restaurant revenue for A-grade restaurants compared to B-grade ones, indicating that consumers respond to hygiene quality information. The study also shows that grade cards led to a 20% decrease in foodborne illness hospitalizations, suggesting that the grade cards have a real impact on restaurant hygiene practices. The study also explores the effects of mandatory and voluntary disclosure of hygiene grade cards. While there are statistically significant differences in the effects on hygiene quality, the differences are small in magnitude. This suggests that firms may voluntarily choose to disclose hygiene grade cards, or they may be anticipating a future mandatory disclosure. The study finds that the effects of mandatory and voluntary disclosure are similar, but the magnitude of the difference is small. The study also discusses the potential impacts of information disclosure on firm behavior, including the mitigation of information asymmetry and the effects on competition among restaurants. The study finds that the introduction of grade cards leads to an increase in restaurant hygiene quality and a decrease in food-related illnesses, suggesting that the grade cards do cause restaurants to improve their hygiene practices. The study concludes that the increased provision of product quality information to consumers does lead to an increase in firms' product quality.