Most of his work is concerned with social networks, migration, and health in Europe and the USA. He is especially interested in the way networks of social interactions, relationships and support develop in immigrant communities and shape immigrants’ lives and health in different countries. He has conducted research on the Sri Lankan community in Italy, West African immigrants in Spain, Roma people in France, and Mexican farm workers in Florida.

He is also interested in the study of science and scientific collaboration, particularly in research related to health and sustainability. Part of his work is methodological research on network analysis and statistical modeling for social network data. He is the author of a textbook on analyzing personal network data (currently under review with SAGE Publications) and the co-author of a textbook on conducting personal network research (published by Guilford Press).

Among his recent publications, we underline:

R Vacca, F Bianchi. Diversity, integration, and variability of intergenerational relationships in old age: New insights from personal network research. Social Science Research 119, 102991 (2024)

K LeBeau, L King, R Vacca. Interorganizational collaboration in a trauma‐informed community: A network analysis of cohesion and change. Journal of Community Psychology 52 (1), 89-104 (2024)

TB Smith, R Vacca, L Mantegazza, I Capua. Discovering new pathways toward integration between health and sustainable development goals with natural language processing and network science. Globalization and Health 19 (1), 44 (2023)

D Fanfan, D D’Ingeo, R Vacca, JMR Stacciarini. Navigating Disconnected Social Circles: Experiences and Personal Networks of Latino/a Adolescents in the US Rural South. Youth & Society 55 (3), 469-493 (2023)

F Wyngaerden, R Vacca, V Dubois, V Lorant. The structure of social support: a multilevel analysis of the personal networks of people with severe mental disorders. BMC psychiatry 22 (1), 698 (2022)

R Vacca, D Cañarte, T Vitale. Beyond ethnic solidarity: The diversity and specialisation of social ties in a stigmatised migrant minority. Journal of Ethnic and Migration Studies 48 (13), 3113-3141 (2022)

E Bohnett, R Vacca, Y Hu, D Hulse, D Varda. Resilience and fragmentation in healthcare coalitions: The link between resource contributions and centrality in health-related interorganizational networks. Social Networks 71, 87-95 (2022)

R Vacca, JMR Stacciarini, M Tranmer. Cross-classified multilevel models for personal networks: Detecting and accounting for overlapping actors. Sociological Methods & Research 51 (3), 1128-1163 (2022)