The Impact of Public Comments: A Quantitative Study of Public Engagement in the NEPA Process

The National Environmental Policy Act (NEPA) serves as the foundational environmental legislation, aiming to merge environmental decision-making with democratic processes, resulting in environmentally conscious outcomes. Enacted in 1970, NEPA mandates a comprehensive environmental review process that assesses the social and environmental impacts of federal decisions. It is a procedural law emphasizing transparency and accountability, hypothesizing that public involvement enhances agency decisions. Current literature on public participation has been primarily theoretical, and broad, quantitative assessments of NEPA documents are limited. This study's objective is to evaluate elements of public participation in NEPA processes and its influence on the outcomes of actions conducted by US Federal Agencies. To address this, we created a rubric based on the theoretical work from previous literature on public participation. This rubric can be broken down into three criteria: how public comments are considered, what opportunities are provided for the public to engage in the NEPA process, and what is the extent of engagement. We assessed how often public comments lead to modification of alternatives, mitigation, or the selection of a new agency preferred alternative. In addition, we collected information on the public participation process outlined in the document. We randomly selected a total of 108 Environmental Impact Statement (EIS) processes based on agency and action type. Our data show that overall, agencies may not be selecting an entirely new preferred alternative, but they are refining plans by modifying alternatives and mitigation in response to public comments. The data suggests that the driving forces behind these changes lie outside of the opportunities provided to engage and the quality of public participation.