Alan Krueger was one of the most prolific and influential economists of his generation. While his research extended into many different areas, including environmental economics,macroeconomics, and behavioral economics, he identifiedfirst and foremost as a “labor economist.”Hewas a labor economist par excellence, always pushing the field in a new (or long overlooked) direction while maintaining the highest standards for the quality and credibility of his empirical findings. The papers in this issue, written by his students and colleagues in labor economics, pay tribute to some of his major contributions to our field. Virtually every paper builds on one or more of Alan’s ideas. Alan earned his bachelor’s degree in industrial and labor relations from Cornell in 1983. His early education included classes in labor economics and statistics that informed his work throughout his career, including a deep appreciation of the value of original data. Thiswas reflected in the surveys at the heart of many of his best-known papers—including his studies of minimum wages (Katz and Krueger 1992; Card and Krueger 1994), twins (Ashenfelter and Krueger 1994), well-being (Kahneman et al. 2004), and wage posting (Hall and Krueger 2012)—and by his founding of the Survey Research Center at Princeton in 1993. Alan’s 1987 dissertation at Harvard focused on wage determination—a topic he returned to often. The first chapter, which was his job market paper and was later published in theQuarterly Journal of Economics (Krueger 1991), is remarkable for the bold simplicity of its design. Alan proposed to

The United States and Canada are as close economically and socially as any pair of countries in the world. They share similar cultural traditions and economic institutions. They are also closely linked by trade and multinational firms that operate on both sides of the border. Nevertheless, the two countries differ inmany small but important ways that ultimately affect individual outcomes and overall labor market performance. Canada has a more comprehensive set of social programs that tend to be more redistributive than those in the United States. Canada also has a higher rate of immigration, with nearly twice as many immigrants per capita. The Canadian economy is more reliant on the natural resource sector, while the United States has a larger tech sector. The United States has a wider distribution of income, with higher poverty rates and a higher share of people with earnings far above themedian salary. It also experienced a far deeper and longer-lasting recession in 2007–8, the consequences of which are still being analyzed and debated. There is a long tradition in social science of using comparisons between the United States and Canada to uncover the impacts of different institutions and policies, including work in political science (e.g., Lipset 1990), criminology (e.g., Sloan et al. 1988), medicine (e.g., Gorey et al. 2009), demography (e.g., Boyd 1976), and labor relations (e.g., Meltz 1985). Building on this tra-

A special exemption from the 1986 Age Discrimination Act allowed colleges and universities to enforce mandatory retirement of faculty at age 70 until 1994. We construct a survey that permits us to compare faculty turnover rates before and after the law changed at a large sample of institutions with defined contribution pension plans. After the elimination of compulsory retirement the retirement rates of 70- and 71-year-olds fell by two-thirds and were comparable to rates of 69-year-olds. These findings indicate that U.S. colleges and universities will experience a rise in the number of older faculty over the coming years.

Between 1965 and 1975 the enrollment rate of college-age men in the United States rose and then fell abruptly. Many contemporary observers (e.g., James Davis and Kenneth Dolbeare, 1968) attributed the surge in college attendance to draft-avoidance behavior. Under a policy first introduced in the Korean War, the Selective Service issued college deferments to enrolled men that delayed their eligibility for conscription. These deferments provided a strong incentive to remain in school for men who wanted to avoid the draft. For example, the college entry rate of young men rose from 54 percent in 1963 to 62 percent in 1968 (the peak year of the draft). Moreover, both the college entry rate and the number of inductions dropped sharply between 1968 and 1973 as the draft was being phased out. Although these parallel trends are suggestive, they do not necessarily prove that draft avoidance raised the education of men who were at risk of service during the Vietnam War. Such an inference requires an explicit specification of the “counterfactual”: What would have happened to schooling outcomes in the absence of the draft? In this paper we use trends in enrollment and completed schooling of men relative to those of women to measure the effects of draftavoidance behavior during the Vietnam War. Our maintained hypothesis is that, in the absence of gender-specific factors such as the draft, the relative schooling outcomes of men and women from the same cohort would follow a smooth trend. In light of the sharp discontinuity in military induction rates between 1965 and 1970, we look for similar patterns in the relative enrollment rate of men, and in the relative college graduation rate of men from cohorts that were at risk of induction during this period.

We use 1980 and 1990 Census data for 119 larger Metropolitan Statistical Areas to examine the effect of skill-group specific immigrant inflows on the location decisions of natives in the same skill group, and on the overall distribution of human capital. To control for unobserved skill-group specific demand factors, our models include lagged mobility flows of natives over the 1970-80 period. We also estimate instrumental variables models that use the fraction of Mexican immigrants in 1970 to predict skill-group specific relative immigrant inflows over the 1980s. Despite wide variation across cities in the size and relative skill composition of immigrant population changes we find no evidence of selective out-migration by natives. We conclude that immigrant inflows exert a direct effect on the relative skill composition of cities: cities that have received relatively unskilled immigrant flows have experienced proportional rises in the size of their unskilled populations.

We review Immigration Economics by George J. Borjas, published in 2014 by Harvard University Press. The book is written as a graduate-level textbook, and summarizes and updates many of Borjas's important contributions to the field over the past thirty years. A key message of the book is that immigration poses significant costs to many members of the host-country labor market. Though the theoretical and econometric approaches presented in the book will be very useful for students and specialists in the field, we argue that the book presents a one-sided view of immigration, with little or no attention to the growing body of work that offers a more nuanced picture of how immigrants fit into the host-country market and affect native workers. (JEL A22, J11, J24, J31, J61, R23)

We study the role of establishment-specific wage premiums in generating recent increases in West German wage inequality. Models with additive fixed effects for workers and establishments are fit into four subintervals spanning the period from 1985 to 2009. We show that these models provide a good approximation to the wage structure and can explain nearly all of the dramatic rise in West German wage inequality. Our estimates suggest that the increasing dispersion of West German wages has arisen from a combination of rising heterogeneity between workers, rising dispersion in the wage premiums at different establishments, and increasing assortativeness in the assignment of workers to plants. In contrast, the idiosyncratic job-match component of wage variation is small and stable over time. Decomposing changes in mean wages between different education groups, occupations, and industries, we find that increasing plant-level heterogeneity and rising assortativeness in the assignment of workers to establishments explain a large share of the rise in inequality along all three dimensions.

Using data for three cohorts of women in the PSID, we show that annual earnings inequality fell sharply between the late 1960s and the mid-1990s, with a large decline in the component attributable to the extensive margin. We then fit earnings-generating models that incorporate both intensive- and extensive-margin dynamics to data for the three cohorts. Our models suggest that more than 80% of the decline in female earnings inequality can be attributed to a weakening of the link between family-based factors (i.e., children and the presence and incomes of partners) and the intensive and extensive margins of earnings determination.