Pre-Analysis Plans (PAPs) for randomized evaluations are becoming increasingly common in Economics, but their definition remains unclear and their practical applications therefore vary widely. Based on our collective experiences as researchers and editors, we articulate a set of principles for the ex-ante scope and ex-post use of PAPs. We argue that the key benefits of a PAP can usually be realized by completing the registration fields in the AEA RCT Registry. Specific cases where more detail may be warranted include when subgroup analysis is expected to be particularly important, or a party to the study has a vested interest. However, a strong norm for more detailed pre-specification can be detrimental to knowledge creation when implementing

field experiments in the real world. An ex-post requirement of strict adherence to pre-specified plans, or the discounting of non-pre-specified work, may mean that some experiments do not take place, or that interesting observations and new theories are not explored and reported. Rather, we recommend that the final research paper be written and judged as a distinct object from the “results of the PAP”; to emphasize this distinction, researchers could consider producing a short, publicly available report (the “populated PAP”) that populates the PAP to the extent possible and briefly discusses any barriers to doing so.

Low-income families in the United States tend to live in neighborhoods that offer limited opportunities for upward income mobility. One potential explanation for this pattern is that families prefer such neighborhoods for other reasons, such as affordability or proximity to family and jobs. An alternative explanation is that they do not move to high-opportunity areas because of barriers that prevent them from making such moves. We test between these two explanations using a randomized controlled trial with housing voucher recipients in Seattle and King County. We provided services to reduce barriers to moving to high-upward-mobility neighbor- hoods: customized search assistance, landlord engagement, and short-term financial assistance. Unlike many previous housing mobility programs, families using vouchers were not required to move to a high-opportunity neighborhood to receive a voucher. The intervention increased the fraction of families who moved to high-upward-mobility areas from 15% in the control group to 53% in the treatment group. Families induced to move to higher opportunity areas by the treatment do not make sacrifices on other aspects of neighborhood quality, tend to stay in their new neighborhoods when their leases come up for renewal, and report higher levels of neighborhood satisfaction after moving. These findings imply that most low-income families do not have a strong preference to stay in low-opportunity areas; instead, barriers in the housing search process are a central driver of residential segregation by income. Interviews with families reveal that the capacity to address each family’s needs in a specific manner – from emotional support to brokering with landlords to customized financial assistance – was critical to the pro- gram’s success. Using quasi-experimental analyses and comparisons to other studies, we show that more standardized policies – increasing voucher payment standards in high-opportunity areas or informational interventions – have much smaller impacts. We conclude that redesigning affordable housing policies to provide customized assistance in housing search could reduce residential segregation and increase upward mobility substantially.

The race between education and technology provides a canonical framework that does an excellent job of explaining US wage structure changes across the twentieth century. The framework involves secular increases in the demand for more-educated workers from skill-biased technological change, combined with variations in the supply of skills from changes in educational access. We expand the analysis backwards and forwards. The framework helps explain rising skill differentials in the nineteenth and twenty-first centuries, but needs to be augmented to illuminate the recent convexification of education returns and implied slowdown in the growth of the relative demand for college workers. Increased educational wage differentials explain 75 percent of the rise of U.S. wage inequality from 1980 to 2000 as compared to 38 percent for 2000 to 2017.

The fall of labor's share of GDP in the United States and many other countries in recent decades is well documented but its causes remain uncertain. Existing empirical assessments typically rely on industry or macro data, obscuring heterogeneity among firms. In this paper, we analyze micro panel data from the U.S. Economic Census since 1982 and document empirical patterns to assess a new interpretation of the fall in the labor share based on the rise of “superstar firms." If globalization or technological changes push sales towards the most productive firms in each industry, product market concentration will rise as industries become increasingly dominated by superstar firms. Since these firms have high markups and a low labor share of value-added and sales, a reallocation of output toward superstar firms depresses the aggregate labor share. We empirically assess seven predictions of this hypothesis: (i) industry sales will increasingly concentrate in a small number of firms; (ii) industries where concentration rises most will have the largest declines in the labor share; (iii) the fall in the labor share will be driven largely by reallocation rather than a fall in the unweighted mean labor share across all firms; (iv) the between firm reallocation component of the fall in the labor share will be greatest in the sectors with the largest increases in market concentration; (v) the industries that are becoming more concentrated will exhibit faster growth of productivity; (vi) the aggregate markup will rise more than the typical firm's markup; and (vii) these patterns should be observed not only in U.S. firms, but also internationally. We find support for all of these predictions.

To monitor trends in alternative work arrangements, we conducted a version of the Contingent Worker Survey as part of the RAND American Life Panel in late 2015. The findings point to a rise in the incidence of alternative work arrangements in the U.S. economy from 1995 to 2015. The percentage of workers engaged in alternative work arrangements – defined as temporary help agency workers, on-call workers, contract workers, and independent contractors or freelancers – rose from 10.7 percent in February 2005 to possibly as high as 15.8 percent in late 2015. Workers who provide services through online intermediaries, such as Uber or Task Rabbit, accounted for 0.5 percent of all workers in 2015. About twice as many workers selling goods or services directly to customers reported finding customers through offline intermediaries than through online intermediaries.

American women are working more, through their sixties and even into their seventies. Their increased participation at older ages started in the late 1980s before the turnaround in older men’s labor force participation and the economic downturns of the 2000s. The higher labor force participation of older women consists disproportionately of those working at full-time jobs. Increased labor force participation of women in their older ages is part of the general increase in cohort labor force participation. Cohort effects, in turn, are mainly a function of educational advances and greater prior work experience. But labor force participation rates of the most recent cohorts in their forties are less than those for previous cohorts. It would appear that employment at older ages could stagnate or even decrease. But several other factors will be operating in an opposing direction leading us to conclude that women are likely to continue to work even longer.

In recent decades, wage inequality in the United States has increased and real wages for less-skilled workers have declined. As a result, many American workers are unable to adequately support their families through work, even working full time. The Earned Income Tax Credit (EITC) has helped to counter this trend and has become one of the nation’s most effective antipoverty policies. But most of its benefits have gone to workers with children. The maximum credit available to workers without dependent children is just over $500, and workers lose eligibility entirely once their annual earnings reach $15,000.

There has been bipartisan support for expanding the EITC for this group of workers. Paycheck Plus is a test of that idea. The program, which provides a bonus of up to $2,000 at tax time, is being evaluated using a randomized controlled trial in two major American cities: New York City and Atlanta, Georgia. This report presents interim findings from the test of Paycheck Plus in New York City. Between September 2013 and February 2014, the project in New York recruited just over 6,000 low-income, single adults without dependent children to take part in the study. Half of them were selected at random to be offered a Paycheck Plus bonus for three years, starting with the 2015 tax season.

Findings

The program sought to mirror the process by which filers apply for the federal EITC, even though the bonus was not administered by the Internal Revenue Service. Participants needed to apply for each bonus, and receipt of it was not automatic with tax filing.

• About 64 percent of individuals in the program group who had earnings in the eligible range received bonuses in the first year (2015), and 57 percent received bonuses in the second year (2016). Among those who received bonuses, the average amount received was $1,400.

• Paycheck Plus increased after-bonus income (earnings plus bonuses) in both years, and increased employment in 2015.

• Paycheck Plus increased tax filing in both tax filing seasons.

• Paycheck Plus increased the payment of child support in 2015.

• Paycheck Plus increased employment in 2015 for most types of participants, although its effects were larger among women than among men.

These findings are consistent with research on the federal EITC showing that an expanded credit can increase after-transfer income and encourage employment without creating work disincentives. Later reports will examine effects after three years on income, work, and other measures of well-being, in both New York City and Atlanta.

The recent fall of labor’s share of GDP in numerous countries is well-documented, but its causes are poorly understood. We sketch a “superstar firm” model where industries are increasingly characterized by “winner take most” competition, leading a small number of highly profitable (and low labor share) firms to command growing market share. Building on Autor et al. (2017), we evaluate and confirm two core claims of the superstar firm hypothesis: the concentration of sales among firms within industries has risen across much of the private sector; and industries with larger increases in concentration exhibit a larger decline in labor’s share.

The share of U.S. workers in alternative work arrangements has increased substantially in recent decades.  Micro longitudinal analyses show that unemployed workers are much more likely to transition into alternative work arrangements than other workers.  Macro time-series evidence shows that weak labor market conditions lead to an increase in non-traditional work.  But the estimated magnitudes imply that Great Recession and high unemployment in the 2000s can account for only a modest part of the rise in alternative work.  Secular factors associated with rising inequality and technological changes making it easier to contract out work appear to be the driving forces.

Roland Fryer is an extraordinary applied microeconomist whose research output related to racial inequality, the US racial achievement gap, and the design and evaluation of educational policies make him a worthy recipient of the 2015 John Bates Clark Medal. I will divide this survey of Roland's research into five categories: the racial achievement gap, education policies and reforms, economics of social interactions, the economics of discrimination and anti-discrimination policies, and further topics involving the black-white racial divide.

The Moving to Opportunity (MTO) experiment offered randomly selected families living in high-poverty housing projects housing vouchers to move to lower-poverty neighborhoods. We present new evidence on the impacts of MTO on children's long-term outcomes using administrative data from tax returns. We find that moving to a lower-poverty neighborhood significantly improves college attendance rates and earnings for children who were young (below age 13) when their families moved. These children also live in better neighborhoods themselves as adults and are less likely to become single parents. The treatment effects are substantial: children whose families take up an experimental voucher to move to a lower-poverty area when they are less than 13 years old have an annual income that is $3,477 (31%) higher on average relative to a mean of $11,270 in the control group in their mid-twenties. In contrast, the same moves have, if anything, negative long-term impacts on children who are more than 13 years old when their families move, perhaps because of disruption effects. The gains from moving fall with the age when children move, consistent with recent evidence that the duration of exposure to a better environment during childhood is a key determinant of an individual's long-term outcomes. The findings imply that offering families with young children living in high-poverty housing projects vouchers to move to lower-poverty neighborhoods may reduce the intergenerational persistence of poverty and ultimately generate positive returns for taxpayers.