Abstract: While a substantial body of work has shown that higher-SES students tend to apply to more selective colleges than their lower-SES counterparts, we know relatively less about why students differ in their application behavior. In this study, we draw upon a sociological approach to educational stratification to unpack the SES-based gap in college application selectivity. Using data from the High School Longitudinal Study of 2009, we examine the contribution of theoretical factors to the class-based gap in the selectivity of college applications. Namely, from the rational action model we estimate the contribution of performance differentials and choice differentials, while from the status attainment model we look at the level and type of educational expectations as well as the number of applications submitted. Through a series of Heckman selection models, as well as a Blinder-Oaxaca decomposition analysis, we can explain 85% of the gap in college application selectivity between students in the top and bottom SES quintiles. In turn, we estimate that 60% of this explained portion is due to rational action mechanisms such as grades and test scores while 35% is due to status attainment mechanisms. Finally, we reveal that SES moderates the relationship between type of expectations and application selectivity. We find that the payoff to higher expectations (in terms of selective applications) disproportionately accrues to higher-SES students.

Universities are increasingly using learning communities (LCs) to promote the academic and social integration of entering students, especially within STEM majors. Examining the causal effect of LCs on student networks is necessary to understand the nature and scope of their impact. This study combines a regression discontinuity design with social network analysis to estimate the effect of a simple LC design on the size, strength, structure, and composition of friendship networks among students within the same biological sciences freshman cohort. Results of the quasi-experimental analysis indicate that LC participants acquired one additional friend in the major and increased their share of friends in the LC by 54 percentage-points. Exponential random-graph models that test mediation and alternative friendship mechanisms provide support for the theoretical argument that the LC promoted friendship development by structuring opportunities for interaction through block-registration into courses. Thus, this study shows that even simple LCs can shape the development of friendships through relatively low-cost administrative means. The increased access to resources and support facilitated by the LC is likely beneficial for participating students. However, there is a potential downside when eligibility for participation is determined using academic metrics that separate the student population into distinct classroom environments.