I document trends in local industrial concentration from 1976 through 2015 and estimate effects of concentration on earnings outcomes. Local concentration generally declined over that period, unlike national concentration, which declined sharply in the early 1980s before increasing to nearly its original level beginning around 1990. Increased local concentration reduces earnings and increases inequality. Because average concentration has fallen, the 90/10 earnings ratio was six percent lower and earnings one percent higher in 2015 than they would have been if local concentration were at its 1976 level. Most demographic subgroups experience mean earnings reductions, and all experience increases in inequality.

中文翻译：

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劳动力市场集中度、收入和不平等

我记录了 1976 年到 2015 年当地工业集中度的趋势，并估计了集中度对收益结果的影响。在此期间，地方集中度普遍下降，这与全国集中度不同，后者在 1980 年代初期急剧下降，然后在 1990 年左右开始上升到接近其原始水平。地方集中度的提高降低了收入并加剧了不平等。由于平均集中度下降，如果本地集中度处于 1976 年的水平，2015 年 90/10 的盈利比率会降低 6%，而盈利会增加 1%。大多数人口子群体都经历了收入减少，并且所有经历的不平等都在加剧。