David (Peilin) Yang is a PhD candidate in Sociology. His research examines how social and spatial contexts—including neighborhood segregation, activity spaces, and the political economy—shape health and aging. One project investigates how immigrant population composition and immigrant selectivity influence our understanding of socioeconomic health disparities in cross-national comparisons between the United States and Canada. Another line of work explores how social participation and employment affect cognitive and functional outcomes in later life.