A zone design approach A zone design approach for investigating inequalities for investigating inequalities

in infant mortalityin infant mortality

Konstantinos Daras (University of East Anglia)

Seraphim Alvanides (University of Newcastle)

Ian Gregory (Queen's University Belfast)

3rd International Population Geographies Conference

19 -21 June 2006, Liverpool, UK

2

The Geography of Infant Mortality The Geography of Infant Mortality in England & Wales (1911-1971)in England & Wales (1911-1971)

Was there a north-south divide?

Looking at inequalities: Between urban/rural LGDs Between/within counties Between/within automated zones

3

Infant Mortality Rate (IMR)Infant Mortality Rate (IMR)

Infant mortality: Deaths before 1st birthday per 1,000 live births

•Social class •Urban/rural

•Low income•Overcrowded•Unhygienic

Infant mortality is related to:

4

Infant Mortality Rates Infant Mortality Rates in England and Wales (1840-1970) in England and Wales (1840-1970)

Wo

rld

Wa

r I

Wo

rld

Wa

r II

(Source: Beaver (1973): p. 244)

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Decline of Infant Mortality Decline of Infant Mortality

Conventional explanations: Cities had high rates because of rapid urban growth Lower rates were driven by improvements in

sanitary conditions in towns and by better health care.

Improvements started simultaneously across the whole country in the 1880s.

After Woods et al (1988 & ’89); Lee (1991); Williams and Galley (1995); Woods (1997)

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Data sources (1)Data sources (1)

The Great Britain Historical GIS (Gregory and Southall, 1998)

1911: 2061 Local Gov. Districts 1928: 2037 Local Gov. Districts 1951: 1527 Local Gov. Districts 1971: 1419 Local Gov. Districts

(Data aggregated to 1971 level)

Infant deaths (before 1st birthday)

Infant births Estimated population Urban/rural classification

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Data sources (2)Data sources (2)

Wo

rld

Wa

r I

Wo

rld

Wa

r II

(Sou

rce:

Bea

ver

(197

3):

p. 2

44)

1881

1928

1931

1911

1951

1971

Available datasets

Phases of inequality change according Lee (1991)

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Measuring InequalitiesMeasuring Inequalities

Gini coefficient Coefficient of variation Variance of logarithms Theil’s entropy index

•Between areas inequalities: Gini coefficient of areas•Within areas inequalities:

N

Ga Ga: Gini coefficient of area aN : number of areas

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Zone DesignZone Design

Aggregation of areal units into zones, so that certain criteria are satisfied.

Available zone design systems AZP (no GIS): Openshaw (1977, 1984) ZDES: Alvanides et al. (1999, 2000) AZM: Martin (2002) A2Z: Daras (2005), O-O & Graph theory

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How A2Z worksHow A2Z works

ZONE 1ZONE 2

AREAL UNIT

NEW ZONE 2

NEW ZONE 1

OB

JEC

TIV

E F

UN

CT

ION C

ON

TIG

UIT

Y C

HE

CK

• Optimises an objective functionOptimises an objective function• Controls the contiguity of zoneControls the contiguity of zone

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A2Z componentsA2Z components

Initial AggregationInitial Aggregation ( (Random or userRandom or user))

Shape ConstraintsShape Constraints (Weak or Strong compactness(Weak or Strong compactness))

Boundary ConstraintsBoundary Constraints ( (Railway, A road, WardsRailway, A road, Wards))

Objective FunctionObjective Function ( (HomogeneityHomogeneity))

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Zone design settingsZone design settings

62 output zones

Random initial aggregation

Weak shape constraint

Dataset <year>

Objective FunctionSimilarity

Infant MortalityZO

NE

DE

SIG

N

Output Zone M<year>

Dataset <year>

Objective Function Similarity

PopulationZO

NE

DE

SIG

N

Output Zone P<year>

Target IM patterns Target Urban/Rural zones

Infant Mortality RatesInfant Mortality Rates((LGD levelLGD level))

LRDs (1928)0 - 3333 - 6464 - 112112 - 333

LGDs (1928) LRDs (1951)0 - 1818 - 3434 - 5656 - 136

LGDs (1951) LRDs (1971)0 - 88 - 1818 - 3131 - 77

LGDs (1971)

LRDs (1911)0 - 7373 - 116116 - 165165 - 353

LGDs (1911)

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Between LGDs inequalitiesBetween LGDs inequalities

0.19

0.2

0.21

0.22

0.23

0.24

0.25

0.26

0.27

1911 1928 1951 1971

Year

Gin

i co

effi

cien

t

All

Urban

Rural

1911 Counties58 - 9393 - 111111 - 130130 - 154

1928 Counties38 - 4848 - 5858 - 6868 - 92

1951 Counties18 - 2626 - 2929 - 3434 - 55

1971 Counties7 - 1515 - 1717 - 1919 - 26

Infant Mortality RatesInfant Mortality Rates((County levelCounty level))

Output zones (1911)62 - 9595 - 114114 - 146146 - 174

Output zones (1928)0 - 3333 - 5656 - 7575 - 92

Output zones (1951)14 - 2525 - 3131 - 4040 - 51

Output zones (1971)6 - 1010 - 1616 - 2020 - 29

Infant Mortality RatesInfant Mortality Rates((output zones based on output zones based on the similarity of IMRthe similarity of IMR))

Output Zones (1911)77 - 9999 - 123123 - 143143 - 168

Output Zones (1928)77 - 5656 - 6868 - 87

Output Zones (1951)18 - 2424 - 2929 - 3535 - 45

Output Zones (1971)0 - 77 - 1616 - 2020 - 28

Infant Mortality RatesInfant Mortality Rates((output zones based on output zones based on

the similarity of populationthe similarity of population))

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Between areas inequalityBetween areas inequality

0.06

0.08

0.1

0.12

0.14

0.16

0.18

1911 1928 1951 1971

Year

Gin

i co

effi

cien

t

County

Inf. Zone

Pop. Zone

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Within areas inequalityWithin areas inequality

0.15

0.16

0.17

0.18

0.19

0.2

0.21

0.22

0.23

1911 1928 1951 1971

Year

Gin

i co

effi

cien

t

County

Inf. Zone

Pop. Zone

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Summary (1)Summary (1)

There has been a steady decline in infant mortality since the 1900s

This masks some complex geographical variations: Between urban area inequalities remained fairly constant

in 1928 and 1951 Between rural area inequalities increased throughout the

study period The automated zones suggest a decline of inequalities in

1951, while the counties record such reduction in 1971 Possible explanation: at period 1928 -1951 urban

inequalities remain steady because of better health care.

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Summary (2)Summary (2)

Traditional descriptions and explanations of these are limited and over-simplified

This method allows comprehensive description but does not provide explanation

Zone design can provide a useful tool for highlighting problems.

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Further researchFurther research

North/South divide: 1911- 2001 Automated zones (2 zones)

Further investigation of 1928 – 1951 period- - - - -

Different aggregation levels (scale) Extend the analysis of IM inequalities

on annually data 1911-2001 Any available socio-economic data

(possible explanations).

A zone design approach A zone design approach for investigating inequalities for investigating inequalities

in infant mortalityin infant mortality

Konstantinos Daras (k.daras@uea.ac.uk)

Seraphim Alvanides (s.alvanides@ncl.ac.uk)

Ian Gregory (ian.gregory@queens-belfast.ac.uk)

3rd International Population Geographies Conference

19 -21 June 2006, Liverpool, UK