Differing disciplinary traditions and applications have given rise
to several distinct approaches to HIA around the world. Generally
these can be classified into one of three categories-1) community
dialogue, 2) quantitative analysis and 3) bureaucratic pragmatism.
Each of these has its own strengths and limitations that make them
more or less suitable for the analysis of different policy initiatives
in different policy-making contexts.
The focus of this approach is on public participation in decision-making,
with community members actively engaged with planners in raising concerns
and developing ideas for alternatives and/or for the mitigation of
impacts. Assessments tend to be qualitative. When quantitative methods
are used their role is to facilitate better public decision-making;
not to indicate which decision is better. This approach's emphasis
on community participation and consensus-based decision-making is
similar to and may stem from that of the World Health Organization's
"Healthy Cities Movement."
Strengths: This approach
fits well with practices of democratic governance. A broad range of
potential impacts and concerns is considered. Although involving the
public may be perceived as time-consuming, this can actually be a
fairly efficient process for generating ideas about significant concerns
and possible alternatives.
Limitations: It is not
very replicable or testable. Comparisons between projects and with
standards are difficult since there are no common metrics. Decisions
based on this approach may be difficult to support in a litigious
legal system that puts a premium on quantitative "scientific" data.
Issues may also arise about who represents the "community." While
this approach does a good job of highlighting potential impacts, it
is often lacking in the evaluation and documentation of those impacts.
Likewise, levels of uncertainty are not well addressed.
- Fleeman N, Scott-Samuel A. A prospective health impact assessment
of the Merseyside Integrated Transport Strategy (MerITS). Journal
of Public Health Medicine, 2000, 22(3):268-274.
- Winters LY. A prospective health impact assessment of the international
astronomy and space exploration center. Journal of Epidemiology
and Community Health, 2001 55:433-441.
- Landstingsforbundet. Examples of how to start up and implement
Health Impact Assessments (HIA: Stockholm County Council, Southwestern
Health District). Available on-line at: http:www.lf.se/hkb/engelskversion/practice.htm.
Overview: This approach goes beyond the simple quantification
of data to attempt to predict impacts based on a systematic analysis
involving a careful specification of outcomes and program effects,
applying methods from economics, toxicology, risk analysis and especially
epidemiology. While traditional epidemiologic studies focus on estimating
the causal relation between one or more exposures and the occurrence
of a single disease or health outcome in a population, HIAs focus
on the combined impact of one or more interventions (e.g. policies)
on multiple health outcomes. These impacts can be measured in different
ways, including: number of prevented deaths, years of life gained
(or lost) (YLL), quality-adjusted years of life gained (e.g. QALYs
and DALYs), cost-effectiveness ratio (e.g. dollars per QALY) and
net monetary benefit (benefits - costs). By bringing together large
amounts of information in a common metric, these measures facilitate
the comparison of potential impacts of various policy alternatives.
Strengths: Assessments using a systematic quantitative approach
as outlined above are testable and reproducible. They provide common
measures that facilitate comparison of alternatives and on-going
monitoring of program impacts. The apparent objectivity of this
approach makes it legally defensible; however, its assumptions and
uncertainty in projections also make it vulnerable to legal challenge
by competing experts. Methodologies based on a potential-outcomes
model can be applied to cumulative or time-dependent exposures,
such as in computer simulation modeling.
Limitations: These assessments are usually highly time-
and cost-intensive which restricts their widespread application.
Limits on time, money and data usually restrict their focus to single,
unmixed, non-cumulative exposures and only one or a few outcomes,
limiting their usefulness as a tool for evaluating policies with
multiple outcomes. While this type of quantitative assessment may
tend to be more objective than other approaches, it involves numerous
value- and model-based assumptions that may or may not be made explicit.
Assumptions are especially problematic for HIAs utilizing the "burden
of disease" approach, since these methods examine the impacts of
outcomes extant in the population, not the impact of interventions
- Ale BJ, Piers M. The assessment and management of third party
risk around a major airport. Journal of Hazardous Materials, 2000,
- De Hollander EM, Melse JM, Lebret, E, Kramers PGN. An aggregate
public health indicator to represent the impact of multiple environmental
exposures. Epidemiology, 1999, 10(5):606-617.
- Fehr R. Environmental health impact assessment: evaluation
of a ten-step model. Epidemiology, 1999, 10(5):618-25.
- Hammitt JK et al. Residential building codes, affordability
and health protection: a risk-tradeoff approach. Risk Analysis,
- Ponce RA et al. Use of quality-adjusted life year weights with
does-response models for public health decisions: a case study
of the risks and benefits of fish consumption. Risk Analysis,
This approach represents a hybrid of the other two approaches, usually
focusing on a specific project, program or policy being considered
for approval by a government agency. It is driven by procedural requirements
to efficiently assess impacts, as specified in a regulation or agency
rule. In contrast, to the "Quantitative Analysis Approach," which
places a premium on accuracy and methodological sophistication, "Bureaucratic
Pragmatism" emphasizes the selection of methods based on regulations
and expediency. A single assessment may consider a range of impacts,
using many different methods from checklists discussed in community
meetings to highly sophisticated computer modeling techniques.
Strengths: This approach can be relatively quick and
efficient, compared to the "Quantitative Analysis Approach," although
agency rules and regulations specifying content and methods can greatly
increase resource requirements for this type of assessment, as has
been the case with environmental impact statements in the U.S. Methods
are usually standardized. There is also usually some requirement for
stakeholder involvement, such as in the scoping and screening of environmental
impact assessments under NEPA.
within this approach, while taking elements of the first two approaches,
may not do either well. Bureaucratic imperatives to make a decision
with limited resources in a limited amount of time, may compromise
the analytic rigor of approach #2, "quantitative analysis," and the
degree of meaningful public participation emphasized in approach #1.
Some analyses may be ad hoc and subjective, with the use of numbers
to give a patina of objectivity and expert sophistication. Public
participation may be limited to nothing more than a vetting of decisions
already made. There is also some question as to whether assessments
are really used in the decision-making process, or whether they are
just conducted to fulfill a bureaucratic requirement.
- Health Canada. The Canadian Handbook on Health Impact Assessment,
2000. Available on-line at: http://www.hc-sc.gc.ca/ehd/oeha/hia.
(In general, the HIA approaches described in this overview of
methods and policies seem to fit best under this category, but
since individual projects are not discussed in detail, this categorization
- Rosenberg BJ et al. The work environment impact assessment:
a methodologic framework for evaluating health-based interventions.
American Journal of Industrial Medicine, 2001, 39:218-226.