Geography Reference
In-Depth Information
For a collection of statistical territorial units
n
, the dissimilarity index
D
is the
sum of all these territorial components, in which
t
i
represents the total population
residing in the territorial unit (
I
) and
m
x
represents the local portion of the observed
minority. The total population of the area in question is noted
T
, while
X
is the
average proportion of the minority for the entire area.
The dissimilarity index ranges from 0 (perfectly mixed residential population, in
which nobody would need to move), to 1, in the case of total residential segregation,
in which the minority must be redistributed to achieve desegregation. The index is
now commonly used in research in the United States in order to understand
residential segregation in urban areas [GLE 01].
In 1970, the value of this index was 0.825 for the African-American population
for the entire United States, as observed at the small scale of block groups. This
means that 82.5% of African-Americans needed to change their area of residence in
order to achieve racial desegregation. In 1970, over one-third of black Americans
(35.5%) lived below the poverty line, a rate two and a half times the national
average at the time (12.6% of the population below the poverty threshold).
The 2000 census provided for an understanding of the evolution of the
conditions of blacks in the United States following the implementation of
affirmative action policies. The number of poor people continued to progress at the
same pace as that of the general population in the United States between 1970 and
2000. More than 12.4% of Americans were considered poor by official standards,
according to the structure of households and their income in the year 1999.
Growth of the African-American population was slightly faster than the national
average, and 34,658 million people claimed a “black” identity at the turn of the
millennium, 53% more than in 1970. In 2004 the black community represented
12.1% of the US population.
The conditions in which blacks live have improved. Their poverty rates fell to
24.9%, which is more than 5 points of progress since 1970. This does represent a
greater number of poor blacks than in 1970, however, and African-Americans
continue to be the majority among the poor population, of which they represent one-
quarter (24%). Residential segregation is declining, but it is still very strong. The
Massey and Denton D index calculated for blacks at the scale of the country's
208,669 BGs is 0.687.
