International Association for Impact Assessment

IA Law, Policies and Practice

Edited By: Bridget

Overview & History

Legislation, policies and practices are distinctive but very related features of the whole range of impact assessment “activities”. Anyone who is familiar with the policy cycle or puzzle is aware of the fact that without policies no legislation can be adopted. But laws serve societal objectives so the practical implementation of the legal framework (from constitutions to administrative orders and contracts) reveals the real political willingness with regard to the concerned legislation as well as the effects of it.

Impact assessment started its institutional career as an environmental policy instrument. Pollution control can be done in a variety of approaches and by applying a range of techniques or instruments, mostly by combining several.

The basic approach, however, to control a potential pollutive activity, is the requirement to submit such an activity to a preventive administrative approval process. The outcome of the formal decision making procedure is usually a consent or permit for the concerned activity1. Even more market oriented approaches like the established US- and EU-emissions trading regimes need to continue to rely on permit requirements as a cornerstone for their systems.

Decision making on proposed activities (projects, plans, programmes and even policies or legislation) should be done on an informed basis and in order to realize that objective, environmental impact assessment (EIA) plays an important role. In addition permits might be changed in case ex post analysis or monitoring produce “new information” and show impacts that are not foreseen or have not been predicted. Furthermore, EIA belongs to the techniques or policy tools, such as inter alia environmental information and liability, for implementing international environmental principles and rules. Many definitions of EIA are available2. During the last decade strategic environmental assessment (SEA) has been developed as the ex ante evaluation tool for planning and even legislative initiatives3. 

Since more than three decades, environmental impact assessments have made their way into the national and international policies and administrative processes, sometimes considered as a separate instrument but also applicable as an element of the (integrated) decision making process.  


1 P.T. STOLL, “Transboundary pollution”, in: F.L. MORRISON & R. WOLFRUM (Eds.), International, regional and national environmental law, Kluwer Law International, The Hague, 2000, 183.

2 J. GLASSON, R. THERIVEL & A. CHADWICK, Introduction to environmental impact assessment, UCL Press, London, 1999 (p. 3) quote Munn: “to identify and predict the impact on the environment and on man’s health and well-being of legislative proposals, policies, programmes, projects and operational procedures, and to interpret and communicate information about the impacts”.

3 Strategic Environmental Assessment has been defined as: "The formalised, systematic and comprehensive process of evaluating the environmental effects of a policy, plan or programme and its alternatives, including the preparation of a written report on the findings of that evaluation, and using the findings in publicly accountable decision-making." in: R. THERIVEL & M. PARTIDARIO, The practice of Strategic Environmental Assessment, Earthscan, London, 1996, 4.; Another definition states: "SEA is a systematic process for evaluating the environmental consequences of proposed policy, plan or programme initiatives in order to pursue they are fully included and appropriately addressed at the earliest stage of decision-making on par with economic and social considerations", in: B. SADLER & R. VERHEEM, Strategic Environmental Assessment: Status, Challenges and Future Directions, Ministry of Housing, Spatial Planning and the Environment/DHV, Amersfoort-The Hague, 1996, 27. See also: S. MARSDEN, Strategic Environmental Assessment in international and European Law, a practitioner’s guide, Earthscan, London, 2008.

World Wide

The 1972 United Nations Stockholm Conference on the Human Environment adopted a number of principles that contain elements to justify the elaboration and application of impact assessments as a policy tool, both at the national and the international level. A more explicit draft text that contained elements for a clearer commitment to environmental impact assessment was not accepted1. In general, Principle 13 of the Stockholm Declaration is considered as containing the rationale for EIA.  

“ In order to achieve a more rational management of resources and thus to improve the environment, States should adopt an integrated and coordinated approach to their development planning so as to ensure that development is compatible with the need to protect and improve environment for the benefit of their population. “

One of the substantive elements of environmental impact assessment is definitely that EIA should strengthen the information basis for the decision makers from a more scientific, independent and impartial perspective. For this purpose Principle 18 of the Stockholm Conference may be recalled: 

“Science and technology, as part of their contribution to economic and social development, must be applied to the identification, avoidance and control of environmental risks and the solution of environmental problems and for the common good of mankind.”2

EIA, however, may not be reduced to an additional scientific reporting phase in the decision making process. It is much more.3 It has to been seen as an element of information disclosure that is also a (environmental) policy instrument.4 EIA also includes a process of which the outcome is the report or statement. This assessment process is ideally a participatory process that incorporates all concerned and relevant stakeholders.5 The report has certainly to be made public before the final decision, as stated in Principle 7 of the Goals and Principles of Environmental Impact Assessment adopted by UNEP in 1987.6 This UNEP document addresses EIA-goals that go beyond the national boundaries:

“1. To establish that before decisions are taken by the competent authority or authorities to undertake or to authorize activities that are likely to significantly affect the environment, the environmental effects of those activities should be taken into account.


2. To promote the implementation of appropriate procedures in all countries consistent with national laws and decision-making processes, through which the foregoing goal may be realized.


3. To encourage the development of reciprocal procedures for information exchange, notification and consultation between States when proposed activities are likely to have significant trans-boundary effects on the environment of those States.”

The Legal Experts Group on Environmental Law of the World Commission on Environment and Development identified environmental assessment as a legal principle of sustainable development and international law.7 So it is not that surprising that EIA made its way into the 1992 Rio Declaration on Environment and Development. Principle 17 of this declaration states:

“Environmental impact assessment, as a national instrument, shall be undertaken for proposed activities that are likely to have a significant adverse impact on the environment and are subject to a decision of a competent national authority.”

Certain commentators read this text as probably containing a requirement to apply EIA (at the national level) as a matter of customary international law, but have also criticized this principle as being limited in its scope.8 On the other hand, Agenda 21, which should have triggered institutional changes towards sustainable development, contains many references to impact assessments in general and EIA in particular.9 The application of EIA is even encouraged in this document and it stresses the need of public participation in EIA procedures.10 The outcomes of the Rio follow-up events (Earth Summit II 199711, Johannesburg 2002) reveal less attention for EIA and impact assessment, but that does not mean that this policy instrument is getting neglected in the practice of sustainable development.12 Within the environmental policy field of numerous states, EIA is certainly established and it has been even commented that EIA as such might be regarded as a general principle of law.13 


1  P. SANDS, Principles of international environmental law, Vol. I, Manchester Un. Press, Manchester, 1995, p. 580. The withdrawal was because developing countries feared the potential of EIA to impede projects, see:  J. HOLDER, Environmental assessment, the regulation of decision making, Oxford Un. Press, Oxford, 2004, 53, footnote 121 

2 Look at:

3 Many descriptions are available, e.g. R. VAN DER VORST, A. GRAFE-BUCKENS & W. SHEATE, “A systematic framework for environmental decision-making”, Journal of Environmental Assessment Policy and Management, Vol. 1, N° 1, March 1999, 4. These authors identified 4 roles for EIA: procedural, informational, preventive and iterative. The last function reflects the fact that the information this process provides, feeds back into the design process of the activity concerned.

4 Information disclosure as a instrument has initially been used more frequently in the US (where NEPA was the first national legislation with EIA requirements) than in Europe, see: J.B. WIENER, “Convergence, divergence, and complexity in US and European risk regulation”, in: N.J. VIG & M.G. FAURE, Green giants? Environmental policies of the United States and the European Union, MIT Press, Cambridge, 2004, 95.

5 P. MACHADO, “Procedural participation under the Environmental Impact Assessment Directive”, Environmental Law Network International (ELNI) Review, 1/2001, 3. 

6 Principle 7: “Before a decision is made on an activity, government agencies, members of the public, experts in relevant disciplines and interested groups should be allowed appropriate opportunity to comment on the EIA.”.

J. HOLDER (2004), 55.

P. SANDS (1995), o.c., 579.

9 L.K. CALDWELL, International environmental policy, Duke University Press, Durham, 1996, 117; also: T. O’RIORDAN & H. VOISEY, “The politics of Agenda 21”, in: T. O’RIORDAN & H. VOISEY, The transition to sustainability, Earthscan, London, 1998, 31.

10 See Para. 23.2 of Agenda 21, Programme of Action for Sustainable Development, see:

11 See Para. 24 (b) of the Programme for further implementation of Agenda 21 that refers to environmental and social impact analysis as part of the policy package to integrate economic, social and environmental objectives.

12 United Nations Division for Sustainable Development Expert Group Meeting on Reviewing National Sustainable Development Strategies (New York, 10 – 11 October 2005) UNDSD/EGM/NSDS/2005/CRP.7 See: presentation by M. JANICKE: “Evaluation of Sustainable Development”, EASY-ECO Conference Manchester, 15 June 2005: The role of ex-ante Environmental Assessment (EIA):

  • Implicit part of the Rio model of environmental governance;
  • Ex-ante assessment already routine as: a) legal assessment (conformity with existing law); b) budgetary assessment (financial need); c) cost-benefit analyses (partly); d) general political assessment (parties, the media).
  • Environmental Impact Assessment should be (and often is) part of this routine;
  • However, its effects depend on certain conditions EIA: Some Caveats;
  • Don‘t overestimate this instrument as a steering mechanism;
  • Policy formulation in a pluralist democracy will never be a technocratic process!
  • Use simple tools and check lists to structure the policy discourse;
  • Extended assessment should be the exception (capacity problem, weak green position in the struggle of expertises, lack of transparency);
  • Integrated Assessment should be mainstreaming not sidelining of environmental criteria.

13 P. BIRNIE & A. BOYLE, International law & the environment, 2nd ed., Oxford University Press, Oxford, 2002, 131.


Proliferation of IA

For decades it has been stressed that without a legal framework environmental impact assessment cannot succeed. So since the introduction of NEPA in the USA all kinds of institutional settings were created to embed impact assessment approaches at the different policy levels. Legislation is the most common way to institutionalize an impact assessment system. So one finds EIA, SEA and other impact assessment requirements in international conventions (e.g. the UNECE Espoo Convention on EIA in a transboundary context), supranational legislation (e.g. directives of the European Union), regional agreements (e.g. the North American Agreement on Environmental Cooperation), and national laws and regulations. Furthermore even within a given jurisdiction such as a national state a range of impact assessment settings may exist. Federal or decentralized states where particular policies have been devolved to subnational levels or lower administrative entities are particular examples of multi-level settings that may complicate the practice of impact assessment.  

Not only at the various institutional levels impact assessment systems have been introduced. A particular evolution has been the proliferation of impact assessments to other sectors, be it as specialized assessments or with a more methodological focus. 

  • Social Impact Assessment
  • Gender Impact Assessment
  • Risk Assessment
  • Life Cycle Analysis
  • Energy Analysis
  • Health Impact Assessment
  • Species Impact Assessment
  • Ecological Impact Assessment
  • Territorial Assessment
  • Technology Assessment
  • Business Impact Assessment
  • Economic Assessment
  • Trade Impact Assessment
  • Sustainability Impact Assessment / Appraisal
  • Cumulative Impact Assessment
  • Extended Impact Assessment
  • Integrated Impact Assessment
  • Regulatory Impact Assessment 

This development has been commented as follows:

“The development of various forms of assessment raises several concerns about their effective implementation, including the resources required, the potential for inconsistencies in approach, the lack of linkages between assessments, and whether the impacts covered are appropriate for broader planning and decision-making purposes.”1

A particular interesting evolution is the ongoing work at the level of the European Union concerning the Better Regulation agenda. As an outcome of both the Sustainable Development Strategy and Lisbon Agenda, impact assessments are becoming more and more embedded in the EU’s regulatory management approach.2

The new guidelines that were introduced in the beginning of 2009 define “Impact assessment” as a set of logical steps to be followed when you prepare policy proposals. It is a process that prepares evidence for political decision-makers on the advantages and disadvantages of possible policy options by assessing their potential impacts. The results of this process are summarized and presented in the IA report. 

In doing an IA, you will have to answer a number of questions: 

  • What is the nature and scale of the problem, how is it evolving, and who is most affected by it?
  • What are the views of the stakeholders concerned?
  • Should the Union be involved?
  • If so, what objectives should it set to address the problem?
  • What are the main policy options for reaching these objectives?
  • What are the likely economic, social and environmental impacts of those options?
  • How do the main options compare in terms of effectiveness, efficiency and coherence in solving the problems?
  • How could future monitoring and evaluation be organised? 

The IA work is a key element in the development of the European Commission proposals, and the College of Commissioners will take the IA report into account when taking its decisions. The IA supports and does not replace decision-making - the adoption of a policy proposal is always a political decision that is made only by the College.


1C. JONES, S. JAY, P. SLINN, C. WOOD, Environmental assessment: dominant or dormant?, in: J. HOLDER & D. McGILLIVRAY, Taking stock of environmental assessment, Law, Policy and Practice, Routledge, 2007, 22.

2 J. WIENER, Better Regulation in Europe, in: J. HOLDER & D. McGILLIVRAY (2007), 65.


IA process management

Legislation offers mostly a basic framework for all stakeholders involved in implementing impact assessment. In practice this framework is supplemented by additional, specific professional guidelines such as technical specifications. But the broader legal setting of the impact assessment procedure is also important and also the administrative culture of a given jurisdiction should not be overlooked as a major influencing factor.

An impact assessment process involves at least a number of categories of participants and given the objective of this process, describing the relationships between these stakeholders in the impact assessment process as an “administrative negotiation process” is quite acceptable.1 This process includes also different dimensions related to rationality, decision making and sustainability, which means that impact assessment serves multiple purposes.2

Table of IA Participant Categories

As the participants or stakeholders have different expectations regarding the process and its outcome given their interests, perceptions and societal values, their opinion about a “good quality Impact Assessment” might differ as well. From this participatory perspective, one may agree with observations in the literature that (E)IA professionals should come to grips with the facts that EIA’s (and SEA’s even more, given their “strategic nature”) are not science and will always contain unexamined and unexplained value assumptions.3 

Some are clear about the ultimate values that have to be pursued: “(…) EIA practitioners, whether regulators, proponents or consultants, are environmental professionals and have an implicit responsibility to work towards a sustainable future. In a busy practice and with the demands of procedural and financial imperatives, it can become easy to slip into a ‘box ticking’ approach to EIA. Vigilance is needed.“ 4

The vigilance however has to go in different directions. The involvement of the public remains an essential element of impact assessment to safeguard the legality of impact assessments as policy influencing tools: “(…) The Achilles-heel of EIA/SEA is public participation, especially when it is carried out as prescribed in the model of communicative reflection. The crucial question is simply whether public participation will take place or not. It is difficult to see any other way of encouraging the general public to participate other than by letting them have real influence on the final decisions, rather than using a great deal of system energy to disguise their ‘participation’ as influence.” 5 

As mentioned before public participation and critique are ways to inform not only decision makers but also consultants and may be helpful in assuring their independence. The use of external expertise (consultants) in the review phase may also be a way to assure (and in the longer term improve) the quality of impact assessments, as far as the availability of capacity allows for this and potential conflicts of interests can be avoided.6 

But one should be aware that even the best intentions and approaches remain vulnerable: “It is difficult to see how the objectives of process transparency and proponent accountability in impact assessment can be met if proponent’s formative value frameworks are not systematically identified and opportunities carved out for them to be challenged, negotiated and, where necessary, changed. Nor can these objectives be met if it is not recognised that uncertainty blind-spots are an inherent characteristic of what appears to have become indispensable integrated impact assessment practice.” 7


1 J. DE HEMPTINNE, La négociation : outil d’aide à la prise de décision et de règlement des conflits environnementaux¸Revue Interdisciplinaire d’ Etudes juridiques (1994) 129-161; also: R. BUCKLEY, Improving the quality of Environmental Impact Statements (EISs), in: Environmental Methods Review: retooling impact assessment for the new century, (A.L. PORTER & J.J. FITTIPALDI , eds, AEPI-IAIA, Fargo, 1998), 42.

2 M. CASHMORE, R. GWILLIAM, R. MORGAN, D. COBB & A. BOND, The interminable issue of effectiveness: substantive purposes, outcomes an research challenges in the advancement of environmental impact assessment theory, Impact Assessment and Project Appraisal, Vol. 22, (2004), 297. 3 R. BEATTIE, Everything you already know about EIA (but don’t often admit), Environmental Impact Assessment Review, Vol. 15 (1995), 109.

4 A. WEAVER, A., POPE, J., A. MORRISON-SAUNDERS, and P. LOCHNER, Contributing to sustainability as an environmental impact assessment practitioner, Impact Assessment and Project Appraisal, Vol. 26, (2008), 97.

5 ELLING, B., “Modernity and communicative reflection in environmental assessment”, presentation on 3 June 2004 during the 3rd Meeting of the Parties of the Espoo Convention (Cavtat).

6 J. SCHOLTEN, Reviewing EISs-EIA reports, in: Report of the EIA process Strengthening Workshop, Canberra 4-7 April, 1995, (IAIA – Environmental Protection Agency, Canberra, 1997), 61.

7 R. DUNCAN, R., Problematic practice in integrated impact assessment: the role of consultants and predictive computer models in burying uncertainty, Impact Assessment and Project Appraisal, Vol. 26, (2008), 64.


Compliance and judicial review

Environmental impact assessment has not only become part of hard law, it has also found its way into the practice of supranational courts and mostly national courts. In the USA court decisions have played a decisive role in the development and the implementation of NEPA and the impact assessment tool. 1

The relevant judgements by the European Court of Justice concern mainly the transposition and application of the EIA Directive (and not yet the SEA Directive).2 Most court decisions of the ECJ reflect an activist interpretation of the EIA Directive and its consecutive amendments. In a number of international environment related disputes that have been addressed by the International Court of Justice, environmental impact assessment has been mentioned in opinions by judges.3 


1 B. KARKKAINEN, NEPA and the curious evolution of environmental impact assessment in the United States, in: J. HOLDER & D. McGILLIVRAY (2007), 55.

2 See e.g. J. HOLDER (2004), 116.

3 In this case however, the ICJ did not say anything on the need for a prior EIA, but focused on the required monitoring of ongoing environmental risks (continuous EIA). More precisely Judge Weeramantry proposed in his separate opinion two international legal principles: (1) continuing EIA and (2) contemporaneity in the application of environmental norms. See: S. TEC & G. ECKSTEIN, “Of solemn oaths and obligations: the environmental impact of the ICJ’s decision in the case concerning the Gabcikovo-Nagymaros project”, in: J. BRUNNEE & E. HEY, Yearbook of International Environmental Law 1997 (Vol. 8), Clarendon Press, Oxford, 1998, 47. 


Special thanks to Jan de Mulder for providing initial content for this IAIA Wiki topic.

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