Frequently, a single-value metric is needed to rank urban regions with respect to the level of multiracial segregation or to compare a segregation level of a single urban region at two different times. Assessment of segregation depends not only on a metric used but also on a choice of region’s partitioning. The standard practice is to partition the region into single-scale subregions. In the United States, census tracts are the subregions of choice. Census aggregation units including tracts are delineated without a direct regard to racial homogeneity and are in fact heterogeneous. Consequently, using tracts as subdivisions leads to the underestimation of the segregation level of the entire region. Here we propose to partition a region into racial enclaves—units having boundaries that align with transitions between different racial compositions. By reflecting true demographic structure, such units minimize their internal racial inhomogeneity resulting in improved assessment of segregation. Enclaves are defined as aggregates of adjacent census blocks (smallest and the most racially homogeneous census units) of similar composition. In a typical US urban region, effective population size of enclaves is an order of magnitude larger than the size of a census tract and yet the segregation calculated based on enclaves is larger than segregation based on census tracts. The proposed methodology is described and applied to a set of 61 largest cities in the US in their metropolitan statistical areas as well as their urban areas boundaries using 1990 and 2010 block-level data. The method is compared to the standard methodology using correlations between cities’ segregation rankings.

通常，需要使用一个单一值的指标来对城市区域的多种族隔离水平进行排名，或者比较一个城市区域在两个不同时间的隔离水平。隔离评估不仅取决于所使用的指标，还取决于区域划分的选择。标准做法是将区域划分为单尺度子区域。在美国，人口普查区是首选的子区域。在不直接考虑种族同质性的情况下，划定了包括人口普查在内的人口普查聚集单位，实际上是异质性的。因此，使用分片来细分会导致对整个区域隔离水平的低估。在这里，我们建议将区域划分为种族飞地-边界与不同种族组成之间的过渡对齐的单位。通过反映真实的人口结构，这些单位将其内部种族不平等程度降至最低，从而改善了对隔离的评估。飞地被定义为相似组成的相邻人口普查区块（最小和种族最均匀的普查单位）的集合。在典型的美国城市地区，飞地的有效人口规模比人口普查区域的规模大一个数量级，但基于飞地计算的隔离度要大于基于普查区域的隔离度。使用1990年和2010年的块级数据描述了所建议的方法，并将其应用于美国61个大城市的大都市统计区域以及其城市边界。使用城市隔离等级之间的相关性，将该方法与标准方法进行了比较。