Census 2000 was the first to allow respondents to identify themselves using multiple race categories. This change raises concerns of how to classify multi-race individuals when making demographic comparisons over time. One possibility is to include in the minority group of interest anyone designating themselves as a member of that racial group, e.g., people who self-identified as Black or African American alone or in combination with another group. An alternative is to include in a group's count only individuals identifying with that group alone. We have decided to use the first method ("alone or in combination") in this report for reasons described in chapter two. This means that the minority group definitions used in this report are not mutually exclusive. The purpose of this appendix is to show how segregation statistics differ across the two racial classification schemes. The reference group-- non-Hispanic Whites-- is always defined as those who report being White alone, and who are not of Hispanic origin. The count of Hispanics or Latinos is not affected by this issue since Hispanic ethnicity is determined by a separate census question, and Hispanics or Latinos can be of any race.

Table A-1 indicates that the differences across the methods are generally small across the 19 segregation indexes examined. The indexes in bold are the ones used throughout this report. As might be expected, segregation tends to be a little higher when using the "alone" classification scheme than the "alone or in combination" one (which includes multiracial individuals). Differences tend to be particularly small for both African Americans and Asians and Pacific Islanders; conclusions about the patterns of segregation for these groups would not change if the "alone" methodology were used instead of the "alone or in combination" one. The differences are modestly larger for American Indians and Alaska Natives. Whereas declines in segregation from 1980 to 2000 are registered across four of the five measures used in this report for this group when the "alone or in combination" scheme is used, this number falls to three when the "alone" category is used.