Measuring racial segregation at different geographic scales in Cape Town and Johannesburg

1991-2011

ISIbalo Symposium on Evidence Based Decision Making

12 September 2013

Kevin Parry

Background

Background

Source: Davies (1981)

The level of segregation in South African urban space by census year, between whites and blacks, as measured by the index of dissimilarity

From Christopher (2001)0 = perfect integration; 100 = total segregation

Repeal of the Group Areas Act

Group Areas

Act (1950)

1994 elections

Leve

l of s

egre

gatio

n

Dealing with the apartheid city

Pg 7: Urban settlements should be “spatially and socio-economically integrated, free of racial and gender discrimination and segregation.”

Pg 11: The central prerequisite of meeting urban challenges: to overcome the historical patterns inherent in the apartheid city

Dealing with the apartheid city

Pg 227: Spatial justice: apartheid’s policy of confining particular groups to limited spaces must be reversed.

Pg 457: Social cohesion: improve public spaces and public services to make it easier for South Africans to interact with each other across the racial divide

Measuring racial segregation:Theil’s entropy index

Theil’s entropy index involves two calculations, which measure:

Racial diversity represented by the symbol E

Segregationrepresented by the symbol H

Adapted from Iceland (2004)

E: diversity0No diversity

1.386Perfect diversity

25% 25% 25% 25%

E

E: diversity0No diversity

1.386Perfect diversity

100%

E

H: segregation0Complete

integration

1Complete

segregation

H

E E

E E

E

Methodology

5 476 values of E, one for each small area

1 value of E for entire study area

Values of E for small areas compared to value of E for

entire study area to obtain H for

entire study area

1km2

H2km2

H3km2

H4km2

H5km2

H6km2

H7km2

H8km2

H

1km2

H2km2

H3km2

H4km2

H5km2

H6km2

H7km2

H8km2

H

0.0

1.0

0.5

H

Measuring segregation at different geographic scales: stylised segregation profiles for four regions

Results

Racial diversity (E) scores for 1km2 grid cells: Cape Town, Census 2011

Racial diversity (E) scores for 8km2 grid cells: Cape Town, Census 2011

Racial diversity (E) scores for 1km2 grid cells: Johannesburg, Census 2011

Racial diversity (E) scores for 8km2 grid cells: Johannesburg, Census 2011

Segregation (H) profiles for Cape Town, 1991-2011

Segregation (H) profiles for Johannesburg, 1991-2011

Segregation (H) profiles for Cape Town and Johannesburg, 2011

Conclusion

• In both Johannesburg and Cape Town:

• Residential segregation decreased between 1991 and 2011

• Despite this, segregation remains high in both cities

• Johannesburg exhibits slightly higher segregation at large geographic scales,

compared to Cape Town

• Cape Town exhibits slightly higher segregation at small geographic scales,

compared to Johannesburg

Thank you!

References

Christopher PJ 2001b. Monitoring segregation levels in South African cities: 1911-1996. South African Geographical Journal 83, 3:

249-257.

Davies RJ 1981. The spatial formation of the South African city. GeoJournal Supplementary Issue 2: 59-72.

Donaldson R & Kotze N 2006. Residential desegregation dynamics in the South African city of Polokwane (Pietersburg).  Tijdschrift

voor Economische en Sociale Geografie 97, 5: 567-582

Horn A 2005. Measuring multi-ethnic spatial segregation in South African cities. South African Geographical Journal 87, 1: 58-72.

Iceland J 2004. The Multigroup Entropy Index (Also Known as Theil’s H or the Information Theory Index). University of Maryland.

Available from: http://www.census.gov/hhes/www/housing/resseg/multigroup_entropy.pdf [Accessed 21 August 2012].

Lee BA, Firebaugh G, Matthews SA, Reardon SF, Farrel CR & O'Sullivan D. 2008. Beyond the Census Tract: Patterns and

Determinants of Racial Segregation at Multiple Geographic Scales. American Sociological Review 73, 5: 766-791.

South Africa (Republic of) 1997. Urban development framework. Pretoria: Department of Housing. 

South Africa (Republic of) 2012. National Development Plan 2030: Our future – make it work. Pretoria: National Planning

Commission.