Capital and Labor: The Factor Income Composition of Top Incomes in the United States, 1962–2006
研究发现美国自1980年代以来资本与劳动收入关联增强，加剧了顶层1%收入份额上升，且该关联呈U型趋势，并检验了不同收入定义下的稳健性。
Abstract This paper finds that capital and labor incomes in the United States have become more closely associated since the 1980s. This has contributed to the well-known increase in the top 1% share of total income, exacerbating rising inequality in capital incomes and earnings. We show that the trend in the association is U-shaped as the recent increase contrasts with a tendency toward a weakening association until the 1980s. The paper, using data derived from tax records, studies the asymmetries in the association and tests for robustness to alternative income definitions, including the role of income from closely held businesses at the top.