Recent trends in income segregation in metropolitan regions show that, after a decline in the 1990s, there was an increase in 2000–2010 that reinforced concerns about the overall growth in U.S. income inequality since the 1970s. Yet the evidence may be systematically biased to exacerbate the upward trend because the effective sample for the American Community Survey (ACS) is much smaller than it was for the 2000 census to which it is being compared. Apparent changes in disparities across census tracts may result partly from a higher level of sampling variation and bias due to the smaller sample. This study uses 100% microdata from the 1940 census to simulate the impact of different sampling rates and applies those approaches to publicly available data for 2000 and 2007–11. The reduction in sample sizes associated with the ACS appears to exaggerate the evidence for increasing income segregation for all measures tested here.

中文翻译：

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收入隔离的上升：真实趋势还是随机抽样变化？

大都市地区收入隔离的最新趋势表明，在 1990 年代下降之后，2000-2010 年有所增加，这加剧了对自 1970 年代以来美国收入不平等总体增长的担忧。然而，由于美国社区调查 (ACS) 的有效样本比与之进行比较的 2000 年人口普查的有效样本小得多，因此证据可能存在系统性偏见，从而加剧了上升趋势。人口普查区域之间差异的明显变化可能部分是由于样本较小而导致较高水平的抽样变异和偏差。本研究使用 1940 年人口普查的 100% 微观数据来模拟不同采样率的影响，并将这些方法应用于 2000 年和 2007-11 年的公开数据。