Essays on Inequality
Name
tadjfar-ntadjfar-phd-economics-2026-thesis.pdf
Size
14.85 MB
Format
Adobe PDF
Checksum (MD5)
ffbd201a08373aac15f9bd72e694dd8b
Author(s)
Tadjfar, Nagisa
Advisor(s)
Autor, David
Gruber, Jonathan
Hendren, Nathaniel
Schilbach, Frank
Date Issued
May 2026
Publisher
Massachusetts Institute of Technology
Abstract
This thesis explores how information, perceptions, and signals of ability perpetuate or alleviate socioeconomic inequality in higher education and early-career labor markets. Universities are viewed as engines of social mobility. At the same time, the use of screening algorithms such as standardized testing is widely criticized for benefiting wealthy students and not capturing the potential of low-income students. In response, many US universities adopted test-optional policies as part of a broader movement away from standardized testing across multiple countries and settings. The first chapter, “Prediction or Prejudice? Standardized Testing and University Access” (co-authored with Kartik Vira), asks whether and how standardized tests inhibit opportunity for low-SES students. We answer this question in the context of the UK’s staggered elimination of pre-university exams in favor of teachers’ predicted exam grades. Eliminating testing increases the university enrollment of low-income students by 3 percentage points (7%), while leaving wealthy students’ enrollment unchanged. Marginal students induced to enroll in university attain employment at better firms and earn £50,000—£100,000 more over their careers, in net present value. Paradoxically, standardized exams exhibit no calibration bias against marginal low-income students—accurately predicting their university success—whereas teacher grades are systematically biased in their favor. Despite proper calibration, standardized tests inhibit low-SES students by deterring human capital investment. When tests are eliminated, 5% of low-income students shift into academic tracks. These findings highlight how disparate impacts can arise even when screening algorithms are unbiased. When the measurement of information itself poses a direct disutility, standardized tests generate disparities that commence earlier in the pipeline. Low-income students are also less likely to apply to and attend elite universities compared to high-income peers with similar academic credentials. What prevents disadvantaged students from applying to elite universities? In many ways, the UK is an ideal setting to explore this question by allowing us to isolate non-financial factors that drive these socioeconomic gaps. In contrast to the US, where students face large heterogeneity and uncertainty in tuition and financial aid, UK students face uniform tuition fees of around $12,000 per year and have access to standardized government loans. The second chapter, “Friends in Higher Places: Social Fit and University Choice” (co-authored with Kartik Vira), examines an understudied driver of university application choices: social exposure to elite universities and beliefs about fitting in. First, we study “breakthrough” events when a school first sends a student to an elite university. After a “breakthrough”, applications to that specific university, but not other elite universities, subsequently rise by 30%. This access promotes upward mobility. Marginal entrants graduate at typical rates and earn £4,000 more annually compared to matched control students, despite coming from relatively poor backgrounds. Why were these students not applying to elite universities previously? Using a field experiment in over 20 high schools, we show that the primary barrier is students’ beliefs about social fit at top universities. At baseline, low-income students are more pessimistic about their chances of fitting in at an elite university, but not about their chances of admission or graduation. Students randomly assigned to view short videos of undergraduates discussing their experiences are 6 percentage points more likely to apply to the speaker’s university. While students’ expectations of fitting in and making friends shift, beliefs about admission chances or graduation do not. Finally, when matched with mentors, students primarily seek out information about social life at university, and the most important factor participants raise with mentors is whether they would fit in and make friends. Our findings highlight perceptions of the social environment at elite universities as a central barrier and illustrate scalable interventions to promote social mobility. The third chapter, “Firms Believing Women Get Less Means They Do” (co-authored with Nancy Wang), studies how inequality persists even when individuals make it into elite universities, secure high-paying jobs, and “do everything right”. We study an employer-driven mechanism behind the early-career gender earnings gap using novel data on MIT graduates’ job offers and negotiation process. We document three key findings. First, women receive lower initial compensation offers than men within an employer-occupation. Second, this gap is entirely concentrated in non-salary components—signing bonus and equity—with no gap in base salary. Third, we find no gender differences in job search, and women negotiate as frequently and successfully as men. These findings also generalize to a national sample of high-skill workers in a dataset from Levels.fyi. We develop a model showing that a small number of discriminatory firms leads all firms in the market to lowball women in equilibrium. This market-wide gender gap is sustained through outside offers and cannot be closed by changes in worker behavior. We validate this mechanism using an incentivized resume evaluation experiment with recruiters, where we find that firms expect other firms to offer women less. Our results highlight the role of firm behavior—rather than worker decisions alone—in perpetuating gender pay disparities. JEL Codes: D91, I23, I24, I26, I28, J71, J78
MIT Department
Massachusetts Institute of Technology. Department of Economics
Terms of Use
In Copyright - Educational Use Permitted
Copyright retained by author(s)
Persistent DSpace Link
