There is growing evidence that our social, economic, and physical environments affect public health. Thus, our health is affected by how buildings and communities are designed, where roadways are located, and what economic, agricultural, and educational policies and programs are implemented. Health can no longer be seen solely as the result of personal choice and behavior. The task of integrating health considerations into such a breadth of activities is potentially daunting. However, a new field—health impact assessment (HIA)—can assist decision-makers in examining the potential health effects of proposed projects, programs, plans, and policies. It has gained momentum internationally, although it is not yet widely used in the United States. Some attribute the difference to the absence of a uniform framework and guidance for conducting such assessments. Given the potential of HIA to improve public health, the Robert Wood Johnson Foundation (RWJF), the National Institute of Environmental Health Sciences (NIEHS), the California Endowment, and the Centers for Disease Control and Prevention (CDC) asked the National Research Council (NRC) to develop a framework, terminology, and guidance for conducting HIA. As a result of that request, NRC convened the Committee on Health Impact Assessment, which prepared this report.
The idea that many factors outside the traditional health field affect public health is not new. In fact, the decrease in mortality from infectious disease in the 19th and 20th centuries and the increase in life expectancy are attributed more to such factors as better nutrition, housing, and sanitation than to advances in medicine (McKeown 1979). Studies have demonstrated the relatively small influence of the medical practice on public health as opposed to the substantial effect of living conditions (Kemm and Parry 2004). Accordingly, many have recognized that improvements in public health will occur only if health consid-
erations are factored into projects, programs, plans, and policies in non-health-related sectors, such as transportation, housing, agriculture, and education (Kemm and Parry 2004; Cole and Fielding 2007).
Given the studies of the determinants of public health, a new field, HIA, arose in the 1980s and 1990s. The most commonly cited definition of HIA was provided in what is known as the Gothenburg consensus paper:
A combination of procedures, methods and tools by which a policy, programme or project may be judged as to its potential effects on the health of a population, and the distribution of those effects within the population (WHO 1999, p. 4).
Other definitions have arisen over the decades, and several examples are provided in Table 1-1. As shown, HIA has been defined in various ways and described by such terms as method, process, approach, tool, and framework. Diverse practices have been associated with HIA, and that diversity has been attributed somewhat to how health has been defined (or not defined) by the various governments and organizations that use HIA. Parry and Kemm (2004), however, asserted that the essential features of HIA are predicting the consequences of various options and educating and assisting decision-makers.
The International Experience
HIA has been used throughout the world to evaluate the potential health consequences of various projects, programs, plans, and policies (see Appendix A for discussion of the international experience in implementing HIA). Europe and such countries as Canada, Australia, and Thailand—and states, provinces, and territories in these countries—have used various approaches to introducing and promoting HIA. Some have integrated it into existing environmental-assessment frameworks or practices, and others have established it as a standalone or distinct process. Some have tried to legislate its use, and others have relied on voluntary processes in which various degrees of government support and resources are provided. Each country’s experience offers different perspectives and lessons to be learned. For example, although the experience in a few countries has suggested that legislation is needed to provide an impetus for conducting HIA, the experience in many other countries has emphasized that legislative requirements alone are not sufficient to ensure its consistent implementation. Education, training, and resources appear to be critical to the success of its use, and engaging traditionally non-health-related sectors and agencies and heightening awareness of HIA also appear to be key.
International organizations have contributed to the development and evolution of HIA. Over the last few decades, the World Health Organization has supported the development and use of HIA through declarations, initiatives,
TABLE 1-1 Selected Definitions of Health Impact Assessmenta
| Definition | Reference | |
| “Any combination of procedures or methods by which a proposed policy or program may be judged as to the effects it may have on the health of a population.” | Frankish et al. 1996 | |
| “A methodology which enables the identification, prediction and evaluation of the likely changes in health risk, both positive and negative, (single or collective), of a policy, programme, plan or development action on a defined population. These changes may be direct and immediate, or indirect and delayed.” | British Medical Association 1998, p. 39 | |
| “The estimation of the effects of a specified action on the health of a defined population.” | Scott-Samuel 1998, p. 704 | |
| “A method of evaluating the likely effects of policies, initiatives and activities on health at a population level and helping to develop recommendations to maximise health gain and minimise health risks. It offers a framework within which to consider, and influence, the broad determinants of health.” | Scottish Office Department of Health 1999, Section 98 | |
| “A means of evidence based policy making for improvement in health. It is a combination of methods whose aim is to assess the health consequences to a population of a policy, project, or programme that does not necessarily have health as its primary objective.” | Scott Samuel 1997 in Lock 2000, p. 1395 | |
| “A multidisciplinary process within which a range of evidence about the health effects of a proposal is considered in a structured framework…based on a broad model of health, which proposes that economic, political, social, psychological, and environmental factors determine population health.” | Grant et al. 2001, p. 1 | |
| “A developing approach that can help to identify and consider the potential—or actual—health impacts of a proposal on a population. Its primary output is a set of evidence-based recommendations geared to informing the decision making process.” | Taylor and Quigley 2002, p. 2-3 | |
| “A structured framework to map the full range of health consequences of any proposal, whether these are negative or positive. It helps clarify the expected health implications of a given action, and of any alternatives being considered, for the population groups affected by the proposals. It allows health to be considered early in the process of policy development and so helps ensure that health impacts are not overlooked.” | WHO 2002, p. 2 |
| Definition | Reference | |
| “A combination of procedures, methods and tools that systematically judges the potential, and sometimes unintended, effects of a policy, plan, programme or project on the health of a population and the distribution of those effects within the population. HIA identifies appropriate actions to manage those effects.” | Quigley et al. 2006, p. 1 | |
| “A combination of procedures, methods, and tools to assess the potential health impacts of a project on nearby populations, and to recommend mitigation measures. HIA addresses both negative and positive aspects of health. HIA will also try to identify benefits to health that may be enhanced.” | IFC 2009, p. 4 |
aKey phrases have been highlighted in the definitions to indicate the various ways that HIA has been defined.
Sources: Krieger et al. 2003; Kemm and Parry 2004.
conferences, workshops, and networks (Cole and Fielding 2007; Forsyth et al. 2010). Its work was driven initially by the need to incorporate HIA into environmental assessments of water-management projects but soon broadened to encourage the use of HIA to define healthy public policies. Multilateral development banks and the International Finance Corporation have also contributed to the development of HIA; many have now adopted standards that include requirements to conduct HIA for projects submitted for funding (IFC 2009; Krieger et al. 2010; Harris-Roxas and Harris 2011).
Many countries and organizations have developed their own guidance on conducting HIA (for example, B.C. Ministry of Health 1994; Fehr 1999; NHS 2000; enHealth 2001; Abrahams et al. 2004; PHAC 2005; Quigley et al. 2006; Harris et al. 2007; IFC 2009; Metcalfe et al. 2009). Regardless of the similarity of the guidance, some have observed that no consistent approach or methods have been used (Kemm 2007; Bhatia 2010). Others have concluded that the criteria for initiating, conducting, and completing HIA need to be clarified (Krieger et al. 2003) and that terminology needs to be standardized (Kemm and Parry 2004). After reviewing numerous examples of HIA, Parry and Kemm (2004, p. 417) concluded that improvements are needed “in terms of methodological techniques and practical application if [HIA] is to truly fulfill its promise and become a useful adjunct to decision making.”
Health Impact Assessment in the United States
In the United States, HIA as a practice independent of environmental or other regulatory impact assessment was first used in San Francisco in 1999 to evaluate a policy to increase the minimum wage (Bhatia and Katz 2001). Although not widely or commonly practiced, HIA has been used in all levels of
government and across the country to evaluate health impacts of proposed projects, policies, plans, and programs. Much of the activity, however, has been centered on local communities, has focused on policies and programs associated with land-use, housing, and transportation planning, and has been sponsored by local public-health and planning agencies, nonprofit organizations, and academic institutions. Several academic institutions—notably the University of California, Berkeley and the University of California, Los Angeles—have helped to advance HIA at the local level by providing training and technical assistance and by developing methods and approaches for conducting HIA.
At the state level, Washington and Massachusetts have passed legislation to support HIA, and several other states—including California, Maryland, Minnesota, and West Virginia—have proposed legislation. Even without legislation, several states—such as Hawaii, Alaska, California, Wisconsin, and Oregon—have been conducting and using HIA to evaluate proposed projects, programs, plans, and policies.
At the federal level, the use of HIA has been largely in the context of implementing the National Environmental Policy Act (NEPA), which requires federal agencies to evaluate the health effects of proposed federal actions [42 U.S.C §§ 4321-4347]. However, the analysis of human health effects has historically been minimized in assessments conducted under NEPA. Several factors—including the lack of focus of early legal claims on human health, misinterpretation of case law, and the lack of involvement of traditionally health-related municipal, state, tribal, or federal agencies in the NEPA process—contributed to the de-emphasis of human health effects. That situation has changed recently with work conducted by native Alaskans to incorporate health, social, and cultural effects into NEPA documents for oil- and gas-leasing programs and leasing sales (BLM 2007; MMS 2007a,b; EPA 2009). That activity has focused attention on and promoted interest in HIA in various federal agencies (see Appendix A for further details on the HIA experience in the United States).
THE COMMITTEE’S TASK AND APPROACH
The committee that was convened in response to the request by RWJF, NIEHS, the California Endowment, and CDC includes experts in HIA, environmental impact assessment, public health, epidemiology, urban planning, social sciences, economics, and decision and risk analysis (see Appendix B for biographies of the committee members). The committee was asked specifically to develop a framework, terminology, and guidance for conducting HIA of proposed policies, programs, and projects at federal, state, tribal, and local levels, including the private sector. The committee was to assess the value and potential value of such assessments; the impediments and countervailing factors that have limited the practice of HIA to date; the circumstances and criteria for conducting HIA; the concepts, tools, and information required; and the types, structure, and content of HIA. On the basis of those considerations, the committee was to de-
velop a systematic conceptual framework and approach for improving the assessment of health impacts in the United States (see Appendix C for the committee’s statement of task).
To accomplish its task, the committee held five meetings. During the first three, public sessions were held in which the committee heard presentations by the sponsors and invited speakers in federal, state, and tribal government; academe; professional associations; nonprofit organizations; and consulting firms. The committee reviewed numerous publications on HIA and considered the experience of various countries and organizations in implementing HIA. A summary of the committee’s review of HIA experience is provided in Appendix A. The committee’s consideration of the literature and the HIA experience shaped its conclusions and recommendations for the framework and guidance that it offers here.
The committee notes that it was given a broad task, that is, to develop a framework and guidance for HIA applicable in all contexts. Therefore, the committee had to develop a flexible framework that is amenable to all types of HIA and could not simply provide a cookbook or technical manual on HIA. The committee, however, has provided extensive reference lists that should help to guide the reader with regard to specific assessments. Furthermore, the committee recognizes that HIA exists on a spectrum of impact assessment and planning tools that have been used for decades. However, the committee’s focus was on developing a framework and guidance for HIA, not on comparing and contrasting all possible approaches and tools that are available. Similarly, although the committee reviewed the international and U.S. experience with HIA, it did not thoroughly examine and compare all types of HIAs that have been conducted or determine their impact and how the information has been used on release of the HIA. Finally, the committee uses various terms throughout the report, many of which are defined in the glossary (see Appendix D). The committee notes that it uses the term public health in this report in the broadest sense possible, that is, generally the health of the public. Implicit in the concept of public health used by the committee is the idea that health is affected by a wide array of factors that range from the societal to the biologic.
The committee’s report is organized into five chapters and six appendixes. Chapter 2 discusses the rationale for conducting HIA and the key role that it can play in improving public health and reducing health disparities. Chapter 3 outlines the elements of the HIA process (that is, the framework), describes the current variability, and highlights features that the committee finds are critical for any HIA. Chapter 4 provides the committee’s suggestions for best practices for conducting HIA, and Chapter 5 discusses what is needed for advancing HIA. The review of HIA experience, the committee biographies, the statement of task,
a glossary of commonly used terms, and a discussion of the analysis of health effects under NEPA are provided in appendixes.
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