PhD thesis defence by Gonçalo Da Silva Lima
This thesis includes three independent essays studying how labor market frictions, socioeconomic diversity in schools, and signals about academic ability affect mortality, educational inequality, and human capital investment decisions.
Chapter 1, joint with Kathrine A. Lorentzen, studies how shortening physicians' work schedules affects healthcare provision and patient mortality. We exploit a 1982 reform in Denmark that strongly restricted hospital doctors' overtime, weekend, and nighttime shifts. Consistent with substitution of workers for hours, vacancies increased by 35% one year after implementation. Using a dose-response difference-in-differences design, we exploit variation in policy intensity across hospital wards with different pre-reform reliance on overtime. We document three main results. First, wards where labor demand changed the most experienced substantial declines in in-hospital mortality rates, especially among emergency admissions. Second, while more physicians led to more planned admissions, better mortality outcomes are not fully explained by shifts in patient composition. Third, persistent post-discharge mortality declines and no change in readmissions or length of stay suggest that gains were not at the expense of higher patient turnover. Our findings are consistent with overtime regulations correcting inefficiently long work hours in a frictional labor market.
Chapter 2, joint with Miguel E. Nunes, studies whether exposure to peers with college-educated parents improves grade progression for children from less-educated households. Using data from Portugal---a country where more than one-fourth of students repeat at least one grade before high school---we exploit within-family variation to control for non-random sorting of parents into schools and time-varying shocks to the household environment. Comparing siblings exposed to different shares of peers with college-educated parents, we find that moving a student from the 10th to the 90th percentile of exposure reduces grade repetition by about one-fifth of the parental-education gap. The estimated effect is roughly one-fourth of the size of the one found in a design that does not restrict comparisons to siblings. Consistent with learning gains from exposure, we show that the effect is partly driven by improved school performance. However, we also show suggestive evidence that schools become more lenient in grade retention decisions when enrolling more students with college-educated parents.
Chapter 3 studies how positive signals of academic ability affect educational choices. I study how receiving a higher grade on a national standardized test affects students' outcomes. For identification, I exploit the random assignment of graders to anonymized tests at the end of middle school, using administrative data from Portugal. I show that there is substantial bunching just above passing thresholds, consistent with graders being lenient. I then use bunching methods to identify the effect of leniency on students' choices. I find that low performers who benefit from lenient grading are significantly less likely to repeat the same school grade and more likely to enroll in a more demanding high-school track. Finally, although graders do not observe test takers' characteristics, I show that leniency correlates with characteristics that can be indirectly inferred from the test itself.
The event will take place in hybrid modality.
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