Expert Report

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Significant improvements in American's health will only occur if health impacts are considered when developing policies, programs, plans, and projects, particularly in sectors that historically have been viewed as unrelated to health, such as transportation, education, agriculture, and housing. Health impact assessment has arisen as an especially promising way to factor health considerations into the decision-making process. It is essentially a structured process that uses scientific data, professional expertise, and stakeholder input to identify and evaluate the public-health consequences of proposals and suggests actions that could be taken to minimize adverse health effects and optimize beneficial ones. This report discusses the need for health-informed decision-making, reviews the current practice of health impact assessment, and provides a framework, terminology, and guidance for improving the assessment of health impacts in the United States.

Key Messages

  • A growing body of research indicates that health is determined by many factors that shape the conditions in which people are born, grow, live, work, and age. For example, public health has been linked to housing policies that determine the quality and location of housing developments, to agricultural policies that influence the availability of healthy food, to urban planning policies that determine land use and street connectivity, to transportation policies that affect the availability of public transportation, and to economic-development policies that affect the location of businesses and industry.
  • Health impact assessment is a tool that can help decision-makers factor health considerations into policy. It is applicable to a broad array of decisions, considers adverse and beneficial effects, can incorporate various types of evidence into the analysis, engage communities and stakeholders in a deliberative process, and offer practical recommendations to improve health.
  • The report’s authoring committee reviewed definitions, practice, published guidance, and peer-reviewed literature on the topic of health impact assessment and developed a six-step framework that organizes and describes the elements of health impact assessment.
  • Several challenges may impede the successful emergence, development, and practice of health impact assessment. These challenges include defining health and the boundaries for health impact assessment; and balancing the need to provide timely, valid information with the realities of varying data quality; producing quantitative estimates of health effects, synthesizing conclusions on dissimilar health effects; engaging stakeholders; ensuring the quality and credibility of health impact assessment; and managing expectations. The committee provided suggestions for addressing these issues.
  • Substantial improvements in public health will require a focused effort to recognize and address the health consequences of decisions at all levels and in all sectors of government. International experience and the limited (but growing) experience in the United States provide important clues as to what is needed most to advance health impact assessment.
  • Providing education and compelling examples of the health implications of decisions would help raise awareness of the many factors that affect health, the importance of considering them in all decision-making, and the role that health impact assessment can play in the decision-making process.
  • Substantial interagency collaboration at the local, state, and federal levels is necessary to conduct health impact assessment, especially those of policies, programs, plans, and projects in nonhealth sectors. Furthermore, systematic use of health impact assessment will depend on the full implementation of current requirements in existing laws—such as the National Environmental Policy Act—and, in certain cases, the adoption of policies and legal mandates to integrate health considerations into decision-making.
  • Because conducting assessments will require the investment of public and private resources, research that documents the effectiveness of health impact assessment at influencing the decision-making process and promoting public health would help to support the field. Moreover, the quality of health impact assessment could be substantially improved with better evidence on the relationship of “distal” factors to health outcomes.
  • Despite acknowledging the need for scholarship in health impact assessment, the committee concluded that health impact assessment is valuable even with a lack of perfect forecasting data and tools because it is better to consider potential health risk and benefits than to ignore them routinely.