In 1956, Thayer "Ted" Scudder and Elizabeth Colson (d. 2016) initiated a study of 57,000 Gwembe Tonga prior to the people's compulsory resettlement in connection with the construction of the Kariba Dam on the Zambezi River. Though both researchers documented the socio-cultural systems, Scudder concentrated on economic activities and the Gwembe Tonga's relationship to the Middle Zambezi Valley. Scudder and Colson returned in 1962 for another year's study to observe how the people coped with resettlement.

In the mid-1960s they decided to extend what had originally been designed and financed as a before and after study by the Rhodes-Livingstone Institute (now part of the University of Zambia) into a more systematic, long-term study. In the 1970s Colson and Scudder recruited and supervised five graduate students who expanded the scope of the Gwembe Tonga Research Program (GTRP) to further include those Gwembe Tonga who had migrated from the Middle Zambezi Valley to rural areas and cities on the Zambian Plateau.

In 1962, while an Assistant Professor at the American University of Cairo, Scudder had the opportunity to undertake a second resettlement study, as a team member of the University's Nubian Ethnographic Survey, of 50,000 Egyptian Nubians prior to their resettlement in connection with the Aswan High Dam. Being the only scholar in the first half of the 1960s with such experience led to dam consultancies and dam advisory positions on panels of environmental and social experts with such organizations as the Ford Foundation, the Food and Agriculture Organization of the UN, the UN Development Programme, the World Health Organization, the World Bank, and the US Agency for International Development. Assignments in over 20 countries in Africa, the Middle East, and Asia enabled Scudder to pioneer the comparative analysis of how up river and down river communities responded to the construction of such large dams as the Ivory Coast's Kossou, Nigeria's Kainji, India's Sardar Sarovar, Laos' Nam Theun 2, and large dams within Sri Lanka's Mahaweli Project.

Scudder founded the non-profit Institute for Development Anthropology (IDA) in 1976 alongside David Brokensha and Michael Horowitz. According to the Institute Brochure, IDA sought to "enhance the ability of low-income populations around the world to defend their human rights through programs and projects designed to promote growth and a more equitable distribution of the world's resources." Between 1976 and 1995, IDA researchers worked throughout the world's late developing countries with special emphasis on river basins in Africa, the Middle East, and Asia, land settlements in South America and elsewhere, household agriculture and livestock management, and community forestry. The Institute closed in the mid-1990s due to a lack of funding and ever-changing national and international factors.