Knowledge that Transforms

This study provides evidence on the relative effectiveness of computer-assisted learning (CAL) software and traditional teaching. Based on a field experiment in Salvadoran primary schools, we evaluate three interventions that aim to improve learning in mathematics: (i) additional teacher-led classes, (ii) additional CAL classes monitored by a supervisor, and (iii) additional CAL classes instructed by a teacher. We find that CAL lessons lead to larger learning gains and are less sensitive to class size as well as student ability than teacher-centered classes. Our results highlight the value of CAL in an environment with heterogeneous classes and poorly qualified teachers.

Firms have discretion over task allocations, which may dampen employees’ career prospects and, hence, their motivation. Task assignments and worker motivation interact through the extent of labor market competition—that is, the possibility of moving to another firm. More competition enhances motivation but decreases firms’ incentives to assign workers to informative tasks. One consequence is that competitive firms sometimes choose strategies that lead to intermediate competition. When the employee pool is heterogeneous, firms might choose different human resource practices that attract different kinds of workers and differentiate themselves through the career opportunities that they offer within and beyond the firm.

Pre-College human capital investment occurs within a competitive environment and depends on market incentives created by Affirmative Action (AA) in college admissions. These policies affect mechanisms for rank-order allocation of college seats, and alter the relative competition between blacks and whites. We present a theory of AA in university admissions, showing how the effects of AA on human capital investment differ by student ability and demographic group. We then conduct a field experiment designed to mimic important aspects of competitive investment prior to the college market. We pay students based on relative performance on a mathematics exam in order to test the incentive effects of AA, and track study efforts on an online mathematics website. Consistent with theory, AA increases average human capital investment and exam performance for the majority of disadvantaged students targeted by the policy, by mitigating so-called "discouragement effects." The experimental evidence suggests that AA can promote greater equality of market outcomes and narrow achievement gaps at the same time.

This study investigates the extent to which economic rents are shared among different types of workers within firms. We utilize administrative payroll records in order to estimate the elasticity of employee compensation with respect to the price of crude oil at petroleum extraction companies. We find that the elasticity of rent sharing is heterogeneous within firms and significantly higher for workers at the top of the earnings distribution. These results can be rationalized by a bargaining model in which insiders within a firm possess greater power to negotiate over wages.

We estimate the nonlinear impact of class size on student achievement by exploiting regulations that cap class size at 20 students per class in kindergarten. Based on student-level information from a previously unexploited and unique large-scale census survey of kindergarten students, this study provides clear evidence of the nonlinearity of class size effects on development measures. While the effects are largest on cognitive development, class size reductions also improve noncognitive skills for children living in disadvantaged areas. These findings suggest that sizeable class size reductions targeted at disadvantaged areas would achieve better results than a marginal reduction across the board.

Measuring occupational mobility from the Current Population Survey using retrospective or longitudinal methods generates substantially different outcomes, in both levels and trends. Using a generalized method of moments technique, we estimate the level of occupational mobility and the measurement error in both of these measures for 1981–2018. We estimate that occupational mobility has been trending down, particularly since 2000, consistent with retrospective measures of occupational mobility. However, estimated mobility is 2–3 percentage points or 60%–70% higher than retrospective measures. Measurement error in longitudinal measures is large and has been worsening over time.

We estimate the impact of macroeconomic conditions on the childcare market. We find that the industry is substantially more exposed to the business cycle than other low-wage industries and responds more strongly to negative shocks than positive ones. Indeed, childcare employment requires more time to recover than the rest of the economy. Although the reduction in supply may pose difficulties for parents, we find evidence that center quality is countercyclical. When unemployment rates are higher, childcare workers have on average higher levels of education and experience, turnover rates are lower, and consumer reviews on Yelp are higher.

I examine worker effort as a potential margin of adjustment to a minimum wage hike using unique data on piece rate workers who perform a homogenous task and whose individual output is rigorously recorded. By employing a difference-in-differences strategy that exploits the increase in Florida’s minimum wage from $6.79 to $7.21 on January 1, 2009, and worker location on the pre-2009 productivity distribution, I provide evidence consistent with incumbent workers’ positive effort responses.

I estimate the effects of exposure to the Great Recession on employment and earnings for groups defined by year of birth over the 10 years following the beginning of the recession. Younger workers experience the largest earnings losses in percentage terms (up to 13%), in part because they remain less likely to work for high-paying employers even as their overall employment recovers more quickly than that of older workers.

We analyze the long-term effects of a high school remedial education program almost two decades after its implementation. Treated students experienced an 11% increase in completed years of postsecondary schooling, a 4% increase in annual earnings, and a significant increase in intergenerational income mobility. These gains reflect improvement of students mainly from below-median-income families. We conclude that the program had gains beyond the short-term significant improvements in high school matriculation exams. A cost-benefit analysis of the program suggests that the government will recover its cost within 7–8 years, implying a very high rate of return.