SIA first emerged in the 1970s in the U.S, as a way to assess the impacts on society of certain development schemes and projects before they go ahead - for example, new roads, industrial facilities, mines, dams, ports, airports, and other infrastructure projects. It has been incorporated since into the formal planning and approval processes in several countries, in order to categorise and assess how major developments may affect populations, groups, and settlements. SIA is often carried out as part of, or in addition to, Environmental Impact Assessment, but it has not yet been as widely adopted as EIA in formal planning systems, often playing a minor role in combined environmental and social assessments.
As to standard definition "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." (International Association for Impact Assessment)
A substantial academic literature has developed around the techniques and the application of SIA, and it is widely taught and practiced. Major consultancy firms offer SIA expertise (which could be offered to 'developers', governments, or campaign organisations). They, and individual skilled practitioners and academics are often called upon to produce SIA reports, particularly in advance of proposed new infrastructure projects. The academic backgrounds of SIA practitioners are diverse, but may include applied sociology, anthropology, geography, development studies, and planning.
SIA overlaps substantially with the current interest in monitoring and evaluation (M&E). M&E is carried out after a project or development has gone ahead, to assess impacts and to see how well its...