<p>This study combines longitudinal and cohort analyses to provide an extensive examination of the nature of postsecondary stratification among Canadian and American universities and students in this era of unprecedented postsecondary expansion, institutional diversification, and rising competition for external research funding. Multiple statistical methods and a range of data sources are employed to analyse new and increasingly important forms of stratification at two levels of analysis: the structural (i.e., universities) and the individual (i.e., students). At the structural level, the results demonstrate that both nations have become more stratified over time. The extent of institutional stratification and rate of growth, however, is much higher in the U.S. At the top end of the U.S. hierarchy, a few '"elite" and larger institutions appear to be winning the majority of contests for economic resources and other independent sources of revenue. In Canada, universities changed only slightly over the span of thirty years, though there is some evidence of mild convergence across nations, particularly in areas where government regulation has become more variable (e.g., endowments, tuitions). At the individual level, even though a wider variety of students from varied social backgrounds are entering into higher education, the analyses reveal a significant degree of inequality in both Canada and the United States. Consistent with existing research, gender remains an important and consistent predictor of school and field of study choices. These educational decisions were also influenced by family background effects, as both parental education and SES exhibited positive and strong influences on institutional selectivity decisions across two U.S. cohorts. For field of study choices, moderate family background effects, strong and consistent academic ability effects and growing academic aspiration effects were found across most analyses, lending support to theories that predict family background has direct and indirect effects on higher education choices. </p> / Thesis / Doctor of Philosophy (PhD)