Teacher Quality at the High-School Level: The Importance of Accounting for Tracks

Unlike in elementary school, high-school teacher effects may be confounded with both selection to tracks and unobserved track-level treatments. I document sizable confounding track effects, and show that traditional tests for the existence of teacher effects are likely biased. After accounting for these biases, high-school algebra and English teachers have much smaller test-score effects than found in previous studies. Moreover, unlike in elementary school, value-added estimates are weak predictors of teachers’ future performance. Results indicate that either (a) teachers are less influential in high school than in elementary school, or (b) test scores are a poor metric to measure teacher quality at the high-school level.

The Effects of an Incentive-Based High-School Intervention on College Outcomes

I analyze the effects of a program that pays both 11th and 12th grade students and teachers for passing scores on Advanced Placement exams on college outcomes. Using a difference-in-differences strategy, I find that affected students of all ethnicities attend college in greater numbers, have improved college GPAs, and are more likely to remain in college beyond their freshman year. Moreover, the program improves college outcomes even for those students who would have enrolled in college without the program. I also find evidence of increased college graduation for black and Hispanic students ─ suggesting that late high-school interventions may confer lasting positive effects on students, and may be effective at improving the educational outcomes of minority students. The finding of enduring benefits when extrinsic motivators are no longer provided is important in light of concerns that incentive-based-interventions may lead to undesirable practices such as “teaching-to-the-test” and cheating.

Can Higher-Achieving Peers Explain the Benefits to Attending Selective Schools?: Evidence from Trinidad and Tobago

Using exogenous secondary school assignments to remove self-selection bias to schools and peers within schools, I credibly estimate both (1) the effect of attending schools with higher-achieving peers, and (2) the direct effect of short-run peer quality improvements within schools, on the same population. While students at schools with higher-achieving peers have better academic achievement, within-school short-run increases in peer achievement improve outcomes only at high-achievement schools. Short-run (direct) peer quality accounts for only one tenth of school value-added on average, but at least one-third among the most selective schools. There are large and important differences by gender.

Teaching Students and Teaching Each Other: The Importance of Peer Learning for Teachers

Using longitudinal elementary school teacher and student data, we document that students have larger test score gains when their teachers experience improvements in the observable characteristics of their colleagues. Using within-school and within-teacher variation, we further show that a teacher’s students have larger achievement gains in math and reading when she has more effective colleagues (based on estimated value-added from an out-of-sample preperiod). Spillovers are strongest for less-experienced teachers and persist over time, teachers perform best when they are the weakest of their peer group, and historical peer quality explains away about twenty percent of the own-teacher effect. These results suggest peer learning

Ability-Grouping and Academic Inequality: Evidence From Rule-Based Student Assignments

[Excerpt] In Trinidad and Tobago students are assigned to secondary schools after fifth grade based on achievement tests, generating large differences in school and peer quality. Using rule-based instrumental variables to address self-selection bias, I find that being assigned to a school with high-achieving peers has large positive effects on examination performance, particularly for girls. This suggests that ability-grouping (or school tracking) reinforces achievement differences by assigning the weakest students to schools that provide the least value-added. While students benefit from attending schools with brighter peers on average, the marginal effect is non-linear such that there are small benefits to attending high-achievement schools over average schools, while there are sizable benefits to attending average schools over low-achievement schools. This suggests that school ability-grouping may harm those consigned to low-achievement schools at the lower end of the achievement distribution

School Competition and Teacher Labor Markets: Evidence from Charter School Entry in North Carolina

I analyze changes in teacher turnover, hiring, effectiveness, and salaries at traditional public schools after the opening of a nearby charter school. While I find small effects on turnover overall, difficult to staff schools (low-income, high-minority share) hired fewer new teachers and experienced small declines in teacher quality. I also find evidence of a demand side response where schools increased teacher compensation to better retain quality teachers. The results are robust across a variety of alternate specifications to account for non-random charter entry.

Ability-grouping and Academic Inequality: Evidence From Rule-based Student Assignments

In Trinidad and Tobago students are assigned to secondary schools after fifth grade based on achievement tests, leading to large differences in the school environments to which students of differing initial levels of achievement are exposed. Using both a regression discontinuity design and rule-based instrumental variables to address self-selection bias, I find that being assigned to a school with higher-achieving peers has large positive effects on examination performance. These effects are about twice as large for girls than for boys. This suggests that ability-grouping reinforces achievement differences by assigning the weakest students to schools that provide the least value-added.

Cost Should Be No Barrier: An Evaluation of the First Year of Harvard\u27s Financial Aid Initiative

This paper evaluates the first year of Harvard’s Financial Aid Initiative, which increased aid and recruiting for students from low income backgrounds. Using rich data from the Census and administrative sources, we estimate family incomes for the vast majority of plausible applicants from the U.S. We find that the Initiative had a significant effect almost entirely because it attracted a pool of applicants that was larger and slightly poorer. It appears that very similar standards of admission were used for this group as had been used in previous years. This group, once admitted, enrolled at a rate very similar to that of previous years. Thus, there are a greater number of low income students in the Class of 2009 than in the Class of 2008 simply because more well-qualified, low income students applied. Put another way, the initiative did not create a new form of affirmative action–rather, there was an untapped supply of able, low income students. Many apparently qualified students still do not apply, and a disproportionate share of these “missing applicants” come from high schools that have little or no tradition of sending applications to selective private colleges. Targeted outreach to such “one offs” – that is, students who are one of only a few qualified students from their school in recent years – may be a way for selective private colleges to increase their income diversity

Do Social Connections Reduce Moral Hazard? Evidence from the New York City Taxi Industry

This study investigates the role of social networks in aligning the incentives of economic agents in settings with incomplete contracts. We study the New York City taxi industry where taxis are often leased and lessee-drivers have worse driving outcomes than owner-drivers as a result of a moral hazard associated with incomplete leasing contracts. Using instrumental variables and fixed-effects analyses, we find that: (1) drivers leasing from members of their country-of-birth community exhibit significantly reduced effects of moral hazard; (2) network effects appear to operate primarily via social sanctions; and (3) network benefits can help to explain the organization of the industry in terms of which drivers and owners form business relationships.

One for the Road: Public Transportation, Alcohol Consumption, and Intoxicated Driving

We exploit arguably exogenous train schedule changes in Washington DC to investigate the relationship between public transportation provision, the risky decision to consume alcohol, and the criminal decision to engage in alcohol–impaired driving. Using a triple differences strategy, we provide evidence that overall there was little effect on DUI arrests, alcohol related fatal traffic and alcohol related arrests. However, we find that these overall effects mask considerable heterogeneity across geographic areas and spatial shifting. Specifically, we find that areas close to bars that are within walking distance to Metro stations experience increases in alcohol related arrests and decreases in DUI arrests.