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Optimizing the two-step floating catchment area method for measuring spatial accessibility to medical clinics in Montreal.

Ngui AN, Apparicio P - BMC Health Serv Res (2011)

Bottom Line: Also, results of the differences between the two methods reveal a clustering of residuals when distance increases.In other words, a low threshold would be associated with a lack of precision.Results of this study suggest that a greater effort must be made ameliorate spatial accessibility to medical clinics in Montreal.

View Article: PubMed Central - HTML - PubMed

Affiliation: Douglas Mental Health University Institute, 6875 Bld, Lasalle, Verdun, Montréal (Québec), H4H 1R3, Canada. andre.ngui@douglas.mcgill.ca

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Comparing accessibility scores of conventional and optimized 2SFCA method.
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Figure 3: Comparing accessibility scores of conventional and optimized 2SFCA method.

Mentions: By computing and evaluating the spatial accessibility index at 500 m, 1 Km, 2 Km and 3 Km shortest network distance, our results show that significant differences exist amongst DAs. Within a distance of 500 meters, the spatial accessibility score ranges from .123 to 3.861 with a standard deviation of .331 which means that within a distance of 500 meters, there is a minimum of .123 medical clinics accessible for 1,000 persons (figure 3). Accessibility scores calculated from the optimized method show greater variability than the conventional method (table 3). However, the optimized method increases more spatial accessibility score. Within a distance of 1 Km, for instance, the maximum clinic accessible for 1,000 persons in one DA, when it is estimated by the conventional method is approximately 2.404, compared with 27.706 physicians for 1,000 potential users when it is estimated by the optimized method. Figure 3 also shows that whatever the method, regions outside the downtown area generally have a much lower spatial accessibility score and this difference tends to increase with the distance. The mean value of the spatial accessibility at 3 Km travel distance is 0.131 for the conventional method and 0.97 for the optimized method. However, considering the very high spatial accessibility score, the size of the population residing in the CBD (Central Business District) area as shown on figure 2, the overall spatial accessibility score of the whole island at a 3 Km level is quite low. The conventional method indicates that the number of medical clinics available for 1,000 persons varies from .014 to .530 and the optimized methods shows that there are between .057 and 4.435 physicians for 1,000 potential users available at 3 Km.


Optimizing the two-step floating catchment area method for measuring spatial accessibility to medical clinics in Montreal.

Ngui AN, Apparicio P - BMC Health Serv Res (2011)

Comparing accessibility scores of conventional and optimized 2SFCA method.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3142205&req=5

Figure 3: Comparing accessibility scores of conventional and optimized 2SFCA method.
Mentions: By computing and evaluating the spatial accessibility index at 500 m, 1 Km, 2 Km and 3 Km shortest network distance, our results show that significant differences exist amongst DAs. Within a distance of 500 meters, the spatial accessibility score ranges from .123 to 3.861 with a standard deviation of .331 which means that within a distance of 500 meters, there is a minimum of .123 medical clinics accessible for 1,000 persons (figure 3). Accessibility scores calculated from the optimized method show greater variability than the conventional method (table 3). However, the optimized method increases more spatial accessibility score. Within a distance of 1 Km, for instance, the maximum clinic accessible for 1,000 persons in one DA, when it is estimated by the conventional method is approximately 2.404, compared with 27.706 physicians for 1,000 potential users when it is estimated by the optimized method. Figure 3 also shows that whatever the method, regions outside the downtown area generally have a much lower spatial accessibility score and this difference tends to increase with the distance. The mean value of the spatial accessibility at 3 Km travel distance is 0.131 for the conventional method and 0.97 for the optimized method. However, considering the very high spatial accessibility score, the size of the population residing in the CBD (Central Business District) area as shown on figure 2, the overall spatial accessibility score of the whole island at a 3 Km level is quite low. The conventional method indicates that the number of medical clinics available for 1,000 persons varies from .014 to .530 and the optimized methods shows that there are between .057 and 4.435 physicians for 1,000 potential users available at 3 Km.

Bottom Line: Also, results of the differences between the two methods reveal a clustering of residuals when distance increases.In other words, a low threshold would be associated with a lack of precision.Results of this study suggest that a greater effort must be made ameliorate spatial accessibility to medical clinics in Montreal.

View Article: PubMed Central - HTML - PubMed

Affiliation: Douglas Mental Health University Institute, 6875 Bld, Lasalle, Verdun, Montréal (Québec), H4H 1R3, Canada. andre.ngui@douglas.mcgill.ca

Show MeSH