When are public comments characterized by high information quality more likely to occur in bureaucratic policymaking? We answer this question using a text-as-data approach applied to an original dataset covering more than 20,000 comments across 1,037 policy acts issued by the European Commission. We construct four measures capturing our multi-dimensional concept of information quality of comments. Our argument emphasizes the interplay between the demand and supply of information provision and highlights the critical role of institutional factors in explaining comments’ information quality. We find that high-quality comments are more likely to emerge during the policy formulation stage and, counterintuitively, in relation to EC policy documents that are informationally dense and syntactically complex. We find no systematic co-variation between a policy area’s established or scientific status and comment quality. Our findings provide novel insights into how the design of public commenting procedures and crafting policy acts shape comments’ information quality.