A recent "revisionist" literature characterizes the pronounced rise in U.S. wage inequality since 1980 as an "episodic" event of the first half of the 1980s driven by nonmarket factors (particularly a falling real minimum wage) and concludes that continued increases in wage inequality since the late 1980s substantially reflect the mechanical confounding effects of changes in labor force composition. Analyzing data from the Current Population Survey for 1963 to 2005, we find limited support for these claims. The slowing of the growth of overall wage inequality in the 1990s hides a divergence in the paths of upper-tail (90/50) inequality-which has increased steadily since 1980, even adjusting for changes in labor force composition-and lower-tail (50/10) inequality, which rose sharply in the first half of the 1980s and plateaued or contracted thereafter. Fluctuations in the real minimum wage are not a plausible explanation for these trends since the bulk of inequality growth occurs above the median of the wage distribution. Models emphasizing rapid secular growth in the relative demand for skills-attributable to skill-biased technical change-and a sharp deceleration in the relative supply of college workers in the 1980s do an excellent job of capturing the evolution of the college/high school wage premium over four decades. But these models also imply a puzzling deceleration in relative demand growth for college workers in the early 1990s, also visible in a recent "polarization" of skill demands in which employment has expanded in high-wage and low-wage work at the expense of middle-wage jobs. These patterns are potentially reconciled by a modified version of the skill-biased technical change hypothesis that emphasizes the role of information technology in complementing abstract (high-education) tasks and substituting for routine (middle-education) tasks. Copyright by the President and Fellows of Harvard College and the Massachusetts Institute of Technology.

This paper analyzes a marked change in the evolution of the U.S. wage structure over the past fifteen years: divergent trends in upper-tail (90/50) and lower-tail (50/10) wage inequality. We document that wage inequality in the top half of distribution has displayed an unchecked and rather smooth secular rise for the last 25 years (since 1980). Wage inequality in the bottom half of the distribution also grew rapidly from 1979 to 1987, but it has ceased growing (and for some measures actually narrowed) since the late 1980s. Furthermore we find that occupational employment growth shifted from monotonically increasing in wages (education) in the 1980s to a pattern of more rapid growth in jobs at the top and bottom relative to the middles of the wage (education) distribution in the 1990s. We characterize these patterns as the "polarization" of the U.S. labor market, with employment polarizing into high-wage and low-wage jobs at the expense of middle-wage work. We show how a model of computerization in which computers most strongly complement the nonroutine (abstract) cognitive tasks of high-wage jobs, directly substitute for the routine tasks found in many traditional middle-wage jobs, and may have little direct impact on non-routine manual tasks in relatively low-wage jobs can help explain the observed polarization of the U.S. labor market. wage inequality. The growth in overall wage inequality was most rapid during the 1980s, and involved a spreading out of the entire wage distribution. Rapid secular growth in the demand for skills, partly driven by skill-biased technical change (SBTC), combined with a sharp slowdown in the growth of the relative supply of college workers (starting in the early 1980s) help to explain these wage changes. The erosion of labor market institutions protecting low-and middlewage workers-the minimum wage and unions-further contributed to rising wage inequality, especially during the 1980s.Recent work challenges these conclusions emphasizing a slowdown in the growth of U.S.wage inequality over the last fifteen years (David Card and John DiNardo 2002; Thomas Lemieux 2006). This "revisionist" literature views the surge in wage inequality of the 1980s as an "episodic" event driven by institutional forces and argues that the more "modest" inequality growth in the 1990s is inconsistent with a key role for SBTC and other market forces.In this paper, we reconsider this revisionist view, focusing on a marked change in the evolution of the U.S. wage structure over the past 15 years: divergent trends in upper-and lowertail wage inequality. In Section I, we document that wage inequality in the top half of the distribution has exhibited an unchecked secular rise for the last 25 years (since 1980), but it has ceased growing since the late 1980s (and for some measures narrowed) in the bottom half of the distribution. In Section II, we show that the pattern of employment growth differed sharply in the 1990s versus the 1980s with more rapid growth of employment in jobs (occupations) at the bott...

Parents invest both material resources and their time into raising their children. Time investment in children is important to the development of human capital. It is also one possible mechanism through which economic status is transmitted from generation to generation. This paper examines parental time allocated to the care of one's children. First, using data from the recent American Time Use Surveys, we highlight what we think are the most interesting cross-sectional patterns in time spent by American parents as they care for their children. (We will refer to the concepts of parental "child care" and parental "time spent with their children" interchangeably, though we discuss in the next section that the two measures might capture different things.) We find that higher-educated parents spend more time with their children; for example, mothers with a college education or greater spend roughly 4.5 hours more per week in child care than mothers with a high school degree or less. This relationship is striking, given that higher-educated parents also spend more time working outside the home. This robust relationship holds across all subgroups examined, including both nonworking and working mothers and working fathers. It also holds across all four subcategories of child care: basic, educational, recreational, and travel related to child care. From an economic perspective, this positive education gradient in child care (and a similar positive gradient found for income)

This paper analyzes a marked change in the evolution of the U.S. wage structure over the past fifteen years: divergent trends in upper-tail (90/50) and lower-tail (50/10) wage inequality. We document that wage inequality in the top half of distribution has displayed an unchecked and rather smooth secular rise for the last 25 years (since 1980). Wage inequality in the bottom half of the distribution also grew rapidly from 1979 to 1987, but it has ceased growing (and for some measures actually narrowed) since the late 1980s. Furthermore we find that occupational employment growth shifted from monotonically increasing in wages (education) in the 1980s to a pattern of more rapid growth in jobs at the top and bottom relative to the middles of the wage (education) distribution in the 1990s. We characterize these patterns as the "polarization" of the U.S. labor market, with employment polarizing into high-wage and low-wage jobs at the expense of middle-wage work. We show how a model of computerization in which computers most strongly complement the nonroutine (abstract) cognitive tasks of high-wage jobs, directly substitute for the routine tasks found in many traditional middle-wage jobs, and may have little direct impact on non-routine manual tasks in relatively low-wage jobs can help explain the observed polarization of the U.S. labor market.

No abstract

A recent "revisionist " literature characterizes the pronounced rise in U.S. wage inequality since 1980 as an "episodic " event of the first-half of the 1980s driven by non-market factors (particularly a falling real minimum wage) and concludes that continued increases in wage inequality since the late 1980s substantially reflect the mechanical confounding effects of changes in labor force composition. Analyzing data from the Current Population Survey for 1963 to 2005, we find limited support for these claims. The slowing of the growth of overall wage inequality in the 1990s hides a divergence in the paths of upper-tail (90/50) inequality --which has increased steadily since 1980, even adjusting for changes in labor force composition --and lower tail (50/10) inequality, which rose sharply in the first-half of the 1980s and plateaued or contracted thereafter. Fluctuations in the real minimum wage are not a plausible explanation for these trends since the bulk of inequality growth occurs above the median of the wage distribution. Models emphasizing rapid secular growth in the relative demand for skills --attributable to skill-biased technical change --and a sharp deceleration in the relative supply of college workers in the 1980s do an excellent job of capturing the evolution of the college/high-school wage premium over four decades. But these models also imply a puzzling deceleration in relative demand growth for college workers in the early 1990s, also visible in a recent "polarization" of skill demands in which employment has expanded in high-wage and low-wage work at the expense of middle-wage jobs. These patterns are potentially reconciled by a modified version of the skill-biased technical change hypothesis that emphasizes the role of information technology in complementing abstract (high-education) tasks and substituting for routine (middle-education) tasks.

A large literature documents a substantial rise in U.S. wage inequality and educational wage differentials over the past several decades and finds that these trends can be primarily accounted for by shifts in the supply of and demand for skills reinforced by the erosion of labor market institutions affecting the wages of low-and middle-wage workers. Drawing on an additional decade of data, a number of recent contributions reject this consensus to conclude that (1) the rise in wage inequality was an "episodic" event of the first-half of the 1980s rather than a "secular" phenomenon, (2) this rise was largely caused by a falling minimum wage rather than by supply and demand factors; and (3)

for helping to shape this article. Any views expressed are those of the authors alone. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. 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.