Population_And_Research_Aggregate encompasses collective entities defined for analytical and research purposes, including both naturally occurring populations and methodologically constructed groups used in social research and policy analysis. These aggregates represent how social scientists and policymakers create categories and samples to understand social phenomena, test theories, and develop policies. They include both target populations that researchers seek to understand and specific methodological tools used to study social processes. These aggregates demonstrate the intersection between social reality and social research, showing how analytical categories and research methods shape our understanding of social phenomena. They are essential for understanding how social knowledge is produced and how research findings are used to inform policy and social intervention.