期刊名称:HIER Discussion Paper Series / Harvard Institute of Economic Research
出版年度:2005
卷号:2005
出版社:Harvard Institute of Economic Research
摘要: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) rising residual wage inequality since the mid-1980s is
explained by confounding effects of labor force composition rather than true
increases in inequality within detailed demographic groups. We reexamine these
claims using detailed data from the Current Population Survey and find only
limited support. Although the growth of overall inequality in the U.S. slowed in
the 1990s, upper tail inequality rose almost as rapidly during the 1990s as
during the 1980s. A decomposition applied to the CPS data reveals large and
persistent rise in within-group earnings inequality over the past several
decades, controlling for changes in labor force composition. While changes in
the minimum wage can potentially account for much of the movement in lower tail
earnings inequality, strong time series correlations of the evolution of the
real minimum wage and upper tail wage inequality raise questions concerning the
causal interpretation of such relationships. We also find that changes in the
college/high school wage premium appear to be well captured by standard models
emphasizing rapid secular growth in the relative demand for skills and
fluctuations in the rate of growth of the relative supply of college workers –
though these models do not accurately predict the slowdown in the growth of the
college/high-school gap during the 1990s. We conclude that these patterns are
not adequately explained by either a ‘unicausal’ skill-biased technical change
explanation or a revisionist hypothesis focused primarily on minimum wages and
mechanical labor force compositional effects. We speculate that these puzzles
can be partially reconciled by a modified version of the skill-biased technical
change hypothesis that generates a polarization of skill demands.