In Project STAR, 11,571 students in Tennessee and their teachers were randomly assigned to classrooms within their schools from kindergarten to third grade. This paper evaluates the long-term impacts of STAR by linking the experimental data to administrative records. We first demonstrate that kindergarten test scores are highly correlated with outcomes such as earnings at age 27, college attendance, home ownership, and retirement savings. We then document four sets of experimental impacts. First, students in small classes are significantly more likely to attend college and exhibit improvements on other outcomes. Class size does not have a significant effect on earnings at age 27, but this effect is imprecisely estimated. Second, students who had a more experienced teacher in kindergarten have higher earnings. Third, an analysis of variance reveals significant classroom effects on earnings. Students who were randomly assigned to higher quality classrooms in grades K-3 -as measured by classmates' end-of-class test scores -have higher earnings, college attendance rates, and other outcomes. Finally, the effects of class quality fade out on test scores in later grades but gains in non-cognitive measures persist.

Are teachers' impacts on students' test scores ("value-added") How can we measure and improve the quality of teaching in primary schools? One prominent but controversial method is to evaluate teachers based on their impacts on students' test scores, commonly termed the "value-added" (VA) approach.

.

NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

We show that the effects of taxes on labor supply are shaped by interactions between adjustment costs for workers and hours constraints set by firms. We develop a model in which firms post job offers characterized by an hours requirement and workers pay search costs to find jobs. We present evidence supporting three predictions of this model by analyzing bunching at kinks using Danish tax records. First, larger kinks generate larger taxable income elasticities. Second, kinks that apply to a larger group of workers generate larger elasticities. Third, the distribution of job offers is tailored to match workers' aggregate tax preferences in equilibrium. Our results suggest that macro elasticities may be substantially larger than the estimates obtained using standard microeconometric methods.

We characterize intergenerational income mobility at each college in the United States using data for over 30 million college students from 1999-2013. We document four results. First, access to colleges varies greatly by parent income. For example, children whose parents are in the top 1% of the income distribution are 77 times more likely to attend an Ivy League college than those whose parents are in the bottom income quintile. Second, children from low-and high-income families have similar earnings outcomes conditional on the college they attend, indicating that low-income students are not mismatched at selective colleges. Third, rates of upward mobilitythe fraction of students who come from families in the bottom income quintile and reach the top quintile-differ substantially across colleges because low-income access varies significantly across colleges with similar earnings outcomes. Rates of bottom-to-top quintile mobility are highest at certain mid-tier public universities, such as the City University of New York and California State colleges. Rates of upper-tail (bottom quintile to top 1%) mobility are highest at elite colleges, such as Ivy League universities. Fourth, the fraction of students from low-income families did not change substantially between 2000-2011 at elite private colleges, but fell sharply at colleges with the highest rates of bottom-to-top-quintile mobility. Although our descriptive analysis does not identify colleges' causal effects on students' outcomes, the publicly available statistics constructed here highlight colleges that deserve further study as potential engines of upward mobility.

Using 41 million observations on savings for the population of Denmark, we show that the impacts of retirement savings policies on wealth accumulation depend on whether they change savings rates by active or passive choice. Subsidies for retirement accounts, which rely upon individuals to take an action to raise savings, primarily induce individuals to shift assets from taxable accounts to retirement accounts. We estimate that each $1 of government expenditure on subsidies increases total saving by only 1 cent. In contrast, policies that raise retirement contributions if individuals take no action-such as automatic employer contributions to retirement accounts-increase wealth accumulation substantially. We estimate that approximately 15% of individuals are "active savers" who respond to tax subsidies primarily by shifting assets across accounts. 85% of individuals are "passive savers" who are unresponsive to subsidies but are instead heavily influenced by automatic contributions made on their behalf. Active savers tend to be wealthier and more financially sophisticated. We conclude that automatic contributions are more effective at increasing savings rates than subsidies for three reasons: (1) subsidies induce relatively few individuals to respond, (2) they generate substantial crowd-out conditional on response, and (3) they do not increase the savings of passive individuals, who are least prepared for retirement. * We thank Do retirement savings policies-such as tax subsidies, employer-provided pensions, and savings mandates-raise total wealth accumulation or simply induce individuals to shift savings across accounts? Despite extensive research, the answer to this question remains unclear, largely due to limitations in data and research designs (Bernheim, 2002). In this paper, we revisit this question using a panel data set with 41 million observations on savings in both retirement and non-retirement accounts for the population of Denmark. We organize our empirical analysis using a stylized model in which the government uses two policies to raise saving: a price subsidy and an automatic contribution that puts part of an individual's salary in a retirement account. We analyze the impacts of these policies on two types of agents: active savers and passive savers. Active savers make savings decisions by maximizing utility, taking into account the subsidies and automatic contributions. Passive savers make fixed pension contributions that are invariant to the automatic contribution and subsidy. The model predicts that automatic contributions should have no impact on total saving-total flows into non-retirement and retirement accounts-for active savers who can fully offset the automatic contribution by reducing their own voluntary pension contributions. In contrast, the impact of automatic contributions on total saving is ambiguous for passive savers. If passive savers absorb the reduction in disposable income due to the automatic contribution by maintaining a fixed consumption plan and running down their bank balanc...

provided outstanding research assistance. Financial support from the Lab for Economic Applications and Policy at Harvard and the National Science Foundation is gratefully acknowledged. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. Publicly available portions of the analysis code are posted at: http://obs.rc.fas.harvard.edu/chetty/va_bias_code.zip NBER working papers are circulated for discussion and comment purposes. They have not been peerreviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.