High levels of ethnoracial diversity are a defining demographic characteristic of U.S. metropolitan areas, but the role of diversity in nonmetropolitan areas is often underappreciated. Here, we use Decennial Census data from 2000 to 2020 to evaluate growing ethnoracial diversity in nonmetropolitan counties and to highlight the uneven geographic distribution of diversity, and changes therein, across nonmetropolitan America. We measure levels of diversity using Simpson's Diversity Index and describe underlying changes in ethnoracial composition. We then produce counterfactual estimates to measure how population change among seven ethnoracial groups has contributed to changes in diversity and compare exposure to diversity across geography and ethnoracial groups. We find that ethnoracial diversity in nonmetropolitan counties has grown by nearly thirty percent in the past twenty years but has remained firmly below that of metropolitan counties. Importantly, nonmetropolitan diversity is increasing due to both growing multiracial and Hispanic populations and the decreasing absolute size of White populations. County‐level exposure to diversity among White populations and populations from minoritized ethnoracial groups has also converged substantially. Overall, growing nonmetropolitan diversity is driven by multiple complex sources and is spatially heterogeneous. Understanding these patterns is important given the centrality of ethnoracial change to the nation's demographic future.

中文翻译：

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美国非大都市和大都市种族多样性的不平衡增长和意外驱动因素☆


高度的民族多样性是美国大都市地区的一个决定性的人口特征，但非大都市地区的多样性的作用往往被低估。在这里，我们使用 2000 年至 2020 年十年一次的人口普查数据来评估非大都市县不断增长的种族多样性，并强调美国非大都市的多样性地理分布不均匀及其变化。我们使用辛普森多样性指数来衡量多样性水平，并描述种族构成的潜在变化。然后，我们进行反事实估计，以衡量七个民族群体之间的人口变化如何影响多样性的变化，并比较不同地理和民族群体对多样性的影响。我们发现，在过去二十年中，非大城市县的种族多样性增长了近百分之三十，但仍明显低于大城市县。重要的是，由于多种族和西班牙裔人口的增长以及白人人口绝对规模的减少，非大都市的多样性正在增加。县级白人人口和少数族裔群体的多样性也大幅趋同。总体而言，不断增长的非大都市多样性是由多个复杂来源驱动的，并且在空间上是异质的。鉴于种族变化对于国家人口未来的中心地位，了解这些模式非常重要。