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Table 4 Spearman rank correlations between measures of the accessibility of hospitals by aggregation method

From: Comparing alternative approaches to measuring the geographical accessibility of urban health services: Distance types and aggregation-error issues

   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
  1. a Aggregation method based on census tract centroid (the least accurate method).
  2. b Aggregation method based on the population-weighted mean of the accessibility measure for dissemination areas within census tracts.
  3. c Aggregation method based on the population-weighted mean of the accessibility measure for blocks within census tracts (the most accurate method).