Table 4

Spearman rank correlations between measures of the accessibility of hospitals by aggregation method

Accessibility measures using shortest network distance

Accessibility measures using shortest network time

Hospitals

CTCa

WDAb

WBlc

CTCa

WDAb

WBlc


Minimum network distance

CTCa

1.000

1.000

WDAb

0.991

1.000

0.987

1.000

0.997

WBlc

0.989

0.997

1.000

0.984

0.997

1.000

Average distance to three closest services

CTCa

1.000

1.000

WDAb

0.997

1.000

0.995

1.000

WBlc

0.997

0.999

1.000

0.994

0.999

1.000

Average distance to five closest services

CTCa

1.000

1.000

WDAb

0.998

1.000

0.996

1.000

WBlc

0.998

0.999

1.000

0.995

0.999

1.000

Average distance to all services

CTCa

1.000

1.000

WDAb

0.998

1.000

0.995

1.000

WBlc

0.999

0.999

1.000

0.995

0.998

1.000

Number of services within 500 metres

CTCa

1.000

1.000

WDAb

0.604

1.000

0.993

1.000

WBlc

0.588

0.838

1.000

0.992

0.999

1.000

Number of services within 1000 metres

CTCa

1.000

1.000

WDAb

0.828

1.000

0.990

1.000

WBlc

0.776

0.924

1.000

0.990

0.998

1.000

Number of services within 2000 metres

CTCa

1.000

1.000

WDAb

0.916

1.000

0.978

1.000

WBlc

0.898

0.968

1.000

0.976

0.996

1.000

Gravity model with α = 1

CTCa

1.000

1.000

WDAb

0.994

1.000

0.992

1.000

WBlc

0.993

0.998

1.000

0.990

0.997

1.000

Gravity model with α = 1.5

CTCa

1.000

1.000

WDAb

0.993

1.000

0.990

1.000

WBlc

0.992

0.996

1.000

0.988

0.996

1.000

Gravity model with α = 2

CTCa

1.000

1.000

WDAb

0.991

1.000

0.987

1.000

WBlc

0.991

0.995

1.000

0.986

0.994

1.000


a Aggregation method based on census tract centroid (the least accurate method).

b Aggregation method based on the population-weighted mean of the accessibility measure for dissemination areas within census tracts.

c Aggregation method based on the population-weighted mean of the accessibility measure for blocks within census tracts (the most accurate method).

Apparicio et al. International Journal of Health Geographics 2008 7:7   doi:10.1186/1476-072X-7-7

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