International Association for Impact Assessment

Social Impact Assessment

Edited By: Bridget

Overview & History


Social Impact Assessment includes the processes of analysing, monitoring and managing the intended and unintended social consequences, both positive and negative, of planned interventions (policies, programs, plans, projects) and any social change processes invoked by those interventions. Its primary purpose is to bring about a more sustainable and equitable biophysical and human environment.

The important features of this definition are that: 

  1. The goal of impact assessment is to bring about a more ecologically, socio-culturally and economically sustainable and equitable environment. Impact assessment, therefore, promotes community development and empowerment, builds capacity, and develops social capital (social networks and trust).
  2. The focus of concern of SIA is a proactive stance to development and better development outcomes, not just the identification or amelioration of negative or unintended outcomes. Assisting communities and other stakeholders to identify development goals, and ensuring that positive outcomes are maximised, can be more important than minimising harm from negative impacts.
  3. The methodology of SIA can be applied to a wide range of planned interventions, and can be undertaken on behalf of a wide range of actors, and not just within a regulatory framework.
  4. SIA contributes to the process of adaptive management of policies, programs, plans and projects, and therefore needs to inform the design and operation of the planned intervention.
  5. SIA builds on local knowledge and utilises participatory processes to analyse the concerns of interested and affected parties. It involves stakeholders in the assessment of social impacts, the analysis of alternatives, and monitoring of the planned intervention.
  6. The good practice of SIA accepts that social, economic and biophysical impacts are inherently and inextricably interconnected. Change in any of these domains will lead to changes in the other domains. SIA must, therefore, develop an understanding of the impact pathways that are created when change in one domain triggers impacts across other domains, as well as the iterative or flow-on consequences within each domain. In other words, there must be consideration of the second and higher order impacts and of cumulative impacts.
  7. In order for the discipline of SIA to learn and grow, there must be analysis of the impacts that occurred as a result of past activities. SIA must be reflexive and evaluative of its theoretical bases and of its practice.
  8. While SIA is typically applied to planned interventions, the techniques of SIA can also be used to consider the social impacts that derive from other types of events, such as disasters, demographic change and epidemics.

SIA is best understood as an umbrella or overarching framework that embodies the evaluation of all impacts on humans and on all the ways in which people and communities interact with their socio-cultural, economic and biophysical surroundings. SIA thus has strong links with a wide range of specialist sub-fields involved in the assessment of areas such as: aesthetic impacts (landscape analysis); archaeological and cultural heritage impacts (both tangible and non-tangible); community impacts; cultural impacts; demographic impacts; development impacts; economic and fiscal impacts; gender impacts; health and mental health impacts; impacts on indigenous rights; infrastructural impacts, institutional impacts; leisure and tourism impacts; political impacts (human rights, governance, democratisation etc); poverty; psychological impacts; resource issues (access and ownership of resources); impacts on social and human capital; and other impacts on societies. As such, comprehensive SIA cannot normally be undertaken by a single person, but requires a team approach.


The nature of SIA in an international context

The objective of SIA is to ensure that development maximises its benefits and minimises its costs, especially those costs borne by people (including those in other places and in the future). Costs and benefits may not be measurable or quantifiable and are often not adequately taken into account by decision-makers, regulatory authorities and developers. By identifying impacts in advance: (1) better decisions can be made about which interventions should proceed and how they should proceed; and (2) mitigation measures can be implemented to minimise the harm and maximise the benefits from a specific planned intervention or related activity.

An important feature of SIA is the professional value system held by its practitioners. In addition to a commitment to sustainability and to scientific integrity, such a value system includes an ethic that advocates openness and accountability, fairness and equity, and defends human rights. The role of SIA goes far beyond the ex-ante (in advance) prediction of adverse impacts and the determination of who wins and who loses. SIA also encompasses: empowerment of local people; enhancement of the position of women, minority groups and other disadvantaged or marginalised members of society; development of capacity building; alleviation of all forms of dependency; increase in equity; and a focus on poverty reduction.

SIA complements the economic and technical models that characterise the thinking of many development professionals and agencies. SIA can be undertaken in different contexts and for different purposes. This creates difficulties in defining or evaluating it. The nature of an SIA done on behalf of a multinational corporation as part of that company’s internal procedures may be very different to an SIA undertaken by a consultant in compliance with regulatory or funding agency requirements, or an SIA undertaken by a development agency interested in ensuring best value for their country’s development assistance. These, in turn, may be very different to an SIA undertaken by staff or students at a local university on behalf of the local community, or an SIA undertaken by the local community itself. Each of these applications of SIA is worthwhile, and none should pretend to be the definitive statement. Evaluation of an SIA needs to consider its intended purpose.

Some conceptualisations of SIA are related to protecting individual property rights, with clear statements of adverse impacts required to ensure that individual rights are not transgressed. Where these rights are violated, SIA could be seen as contributing to mitigation and compensation mechanisms. In these situations, SIA tends to concentrate on the negative impacts. In other contexts, however, particularly in developing countries, there should be less emphasis on the negative impacts on small groups of individuals or on individual property rights. Rather, there should be greater concern with maximising social utility and development potential, while ensuring that such development is generally acceptable to the community, equitable and sustainable.

SIA should also focus on reconstruction of livelihoods. The improvement of social wellbeing of the wider community should be explicitly recognised as an objective of planned interventions, and as such should be an indicator considered by any form of assessment. However, awareness of the differential distribution of impacts among different groups in society, and particularly the impact burden experienced by vulnerable groups in the community should always be of prime concern.


What are social impacts?

SIA is much more than the prediction step within an environmental assessment framework. Social impacts are much broader than the limited issues often considered in EIAs (such as demographic changes, job issues, financial security, and impacts on family life). A limited view of SIA creates demarcation problems about what are the social impacts to be identified by SIA, versus what is considered by related fields such as health impact assessment, cultural impact assessment, heritage impact assessment, aesthetic impact assessment, or gender impact assessment. The SIA community of practitioners considers that all issues that affect people, directly or indirectly, are pertinent to social impact assessment.

A convenient way of conceptualising social impacts is as changes to one or more of the following: 

  • people’s way of life – that is, how they live, work, play and interact with one another on a day-to-day basis;
  • their culture – that is, their shared beliefs, customs, values and language or dialect;
  • their community – its cohesion, stability, character, services and facilities;
  • their political systems – the extent to which people are able to participate in decisions that affect their lives, the level of democratisation that is taking place, and the resources provided for this purpose;
  • their environment – the quality of the air and water people use; the availability and quality of the food they eat; the level of hazard or risk, dust and noise they are exposed to; the adequacy of sanitation, their physical safety, and their access to and control over resources;
  • their health and wellbeing – health is a state of complete physical, mental, social and spiritual wellbeing and not merely the absence of disease or infirmity;
  • their personal and property rights – particularly whether people are economically affected, or experience personal disadvantage which may include a violation of their civil liberties;
  • their fears and aspirations – their perceptions about their safety, their fears about the future of their community, and their aspirations for their future and the future of their children.


Activities comprising SIA

SIA comprises most of the following activities. It: 

  • participates in the environmental design of the planned intervention;
  • identifies interested and affected peoples;
  • facilitates and coordinates the participation of stakeholders;
  • documents and analyses the local historical setting of the planned intervention so as to be able to interpret responses to the intervention, and to assess cumulative impacts;
  • collects baseline data (social profiling) to allow evaluation and audit of the impact assessment process and the planned intervention itself;
  • gives a rich picture of the local cultural context, and develops an understanding of local community values, particularly how they relate to the planned intervention;
  • identifies and describes the activities which are likely to cause impacts (scoping);
  • predicts (or analyses) likely impacts and how different stakeholders are likely to respond;
  • assists evaluating and selecting alternatives (including a no development option);
  • assists in site selection;
  • recommends mitigation measures;
  • assists in the valuation process and provides suggestions about compensation (non-financial as well as financial);
  • describes potential conflicts between stakeholders and advises on resolution processes;
  • develops coping strategies for dealing with residual or non-mitigatable impacts;
  • contributes to skill development and capacity building in the community;
  • advises on appropriate institutional and coordination arrangements for all parties;
  • assists in devising and implementing monitoring and management programs.


Core Values

In the IAIA-endorsed “International Principles for Social Impact Assessment, the SIA community of practice believes that:

  1. There are fundamental human rights that are shared equally across cultures, and by males and females alike.
  2. There is a right to have those fundamental human rights protected by the rule of law, with justice applied equally and fairly to all, and available to all.
  3. People have a right to live and work in an environment which is conducive to good health and to a good quality of life and which enables the development of human and social potential.
  4. Social dimensions of the environment – specifically but not exclusively peace, the quality of social relationships, freedom from fear, and belongingness – are important aspects of people’s health and quality of life.
  5. People have a right to be involved in the decision making about the planned interventions that will affect their lives.
  6. Local knowledge and experience are valuable and can be used to enhance planned interventions.


Fundamental principles for development

In the IAIA-endorsed “International Principles for Social Impact Assessment, the SIA community of practice considers that: 

  • Respect for human rights should underpin all actions.
  • Promoting equity and democratisation should be the major driver of development planning, and impacts on the worst-off members of society should be a major consideration in all assessment.
  • The existence of diversity between cultures, within cultures, and the diversity of stakeholder interests need to be recognised and valued.
  • Decision making should be just, fair and transparent, and decision makers should be accountable for their decisions.
  • Development projects should be broadly acceptable to the members of those communities likely to benefit from, or be affected by, the planned intervention.
  • The opinions and views of experts should not be the sole consideration in decisions about planned interventions.
  • The primary focus of all development should be positive outcomes, such as capacity building, empowerment, and the realisation of human and social potential.
  • The term, ‘the environment’, should be defined broadly to include social and human dimensions, and in such inclusion, care must be taken to ensure that adequate attention is given to the realm of the social.


Principles specific to SIA practice

  1. Equity considerations should be a fundamental element of impact assessment and of development planning.
  2. Many of the social impacts of planned interventions can be predicted.
  3. Planned interventions can be modified to reduce their negative social impacts and enhance their positive impacts.
  4. SIA should be an integral part of the development process, involved in all stages from inception to follow-up audit.
  5. There should be a focus on socially sustainable development, with SIA contributing to the determination of best development alternative(s) – SIA (and EIA) have more to offer than just being an arbiter between economic benefit and social cost.
  6. In all planned interventions and their assessments, avenues should be developed to build the social and human capital of local communities and to strengthen democratic processes.
  7. In all planned interventions, but especially where there are unavoidable impacts, ways to turn impacted peoples into beneficiaries should be investigated.
  8. The SIA must give due consideration to the alternatives of any planned intervention, but especially in cases when there are likely to be unavoidable impacts.
  9. Full consideration should be given to the potential mitigation measures of social and environmental impacts, even where impacted communities may approve the planned intervention and where they may be regarded as beneficiaries.
  10. Local knowledge and experience and acknowledgment of different local cultural values should be incorporated in any assessment.
  11. There should be no use of violence, harassment, intimidation or undue force in connection with the assessment or implementation of a planned intervention.
  12. Developmental processes that infringe the human rights of any section of society should not be accepted.



The legal basis of SIA (and thereby increasing standing and public awareness) first emerged in 1969/1970 when the US National Environment Policy Act (NEPA) introduced a requirement to ensure that major federal actions significantly affecting the quality of the human environment were incorporated into a balanced and publicly available assessment of the likely impact of such actions (Burdge and Vanclay 1995). The inquiry into the proposed Mackenzie Valley gas pipeline from Yukon Territory to Alberta (1974-1978) was the first major EIA case which was overturned for social reasons, due to a failure to consider the impacts on a local tribe. Since then, SIA has been progressively introduced to many countries around the world. 


The SIA Section in IAIA has endorsed the “International Principles for Social Impact Assessment” as being its official understanding of what SIA should be about. The International Principles were developed as an official IAIA Project, with workshops to develop the Principles being held at various IAIA and other conferences across six continents over a five year period. Several hundred people were consulted in the process and some fifty people made substantial contributions to the document. 

Further Reading

IAIA Key Citations: Social Impact Assessment (Updated October 2009)

External Links

Online interactive SIA bibliography 

Annotated SIA bibliography


Special thanks to Ana Maria Esteves and Frank Vanclay for providing initial content for this IAIA Wiki topic.

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