Although increasing racial and ethnic diversity is a demographic trend with society-wide implications, it has advanced farther in some parts of the United States than others. Our research seeks to understand this unevenness at the local level. Drawing on 1980–2010 census data, we use an innovative spatial analytic approach to examine the spread or diffusion of diversity across counties in the 48 contiguous states. Three perspectives—locational persistence, spatial assimilation, and institutional hub—offer different expectations about the nature of the diffusion process. The perspectives are evaluated by mapping changes in the magnitude and structure of diversity and by tracing county transitions between types of diversity clusters. We document considerable stability in diversity patterns over a 30-year period, consistent with the logic of locational persistence. But support is also found for the spatial assimilation and institutional hub models in the form of cluster-type transitions that reflect contagious diffusion and hierarchical diffusion, respectively.

中文翻译：

---

美国各州种族和民族多样性的空间扩散

尽管种族和族裔多样性的增加是一种人口趋势，具有全社会的影响，但在美国某些地区，这种进步远超过其他地区。我们的研究旨在了解当地的这种不平衡。利用1980-2010年的人口普查数据，我们使用一种创新的空间分析方法来检查48个连续州中各县之间的多样性分布或扩散。位置持久性，空间同化和制度中心这三个观点对扩散过程的性质提出了不同的期望。通过绘制多样性的规模和结构变化以及追踪多样性集群类型之间的县际变迁来评估这些观点。我们记录了30年间多样性模式的相当大的稳定性，与位置持久性的逻辑一致。但是，也找到了以集群类型转换形式的空间同化和制度中心模型的支持，这些类型转换分别反映了传染性扩散和等级扩散。