| 1. BackgroundThe spatial accessibility of medical service and the resources is an important factor related to residents’selection and utilization of medical service. It is always necessary to have a whole picture of a region’s medical resources distribution, no matter for the governments to relocate the medical resources or for the investors to decide where to invest. While the most direct way of visualizing is making a map to show the degree of spatial accessibility of every point in a region. How to evaluate the degree of convenience of residents’ access to medical service? Lots of researchers have carried out relevant works. While, most of the evaluations are general and not specific, and there has been no literature published by now to analyze the methods developed systematically. As to related technologies for calculation and visualization, they are existed, but needed to be organized and integrated, and they should be expressed in a way by which scholars from health field are easier to figure out. Focusing on these issues of evaluating spatial accessibility of medical services, this research will precede two main works:(1) systematically analyzing advantages and shortcomings of the methods of spatial accessibility by using these methods to evaluate the spatial accessibility of medical service of Shanghai. This will provide the empirical evidences for finding every shortcoming of these methods one by one, and the methods to make up these shortcomings; (2) excavating related geographic information system technologies, the key points and the process of visualization the spatial accessibility of medical service.2. Research Objectives and ContentsThis research aimed to evaluate and visualize the degree of convenience of the residents’access to different medical services.Research contents includes:(1) research on the methods of evaluating the spatial accessibility of medical service. Based on the data of Shanghai, we will calculate and map the spatial accessibility distribution of Shanghai’s medical service by using the minimum distance method, the ratio method, the 2 step floating method and the gravity method, separately. Through comparing the maps, we will analyze the advantages and shortcomings of these methods and searching for methods to make up the shortcomings. (2) Research on the technologies of visualization. Based on the ArcGIS software of geographic information system, we will explore the key points and technologies of the calculation process of the indexes and the steps of the visualization process.3. Research Methods(1) Literature induction. With the topic of geographic accessibility and the technology of visualization, we reviewed 170journal papers and various statistical data and related books, which provide the theoretical basis and methodological foundation for the research.(2) Expert consultation. We will consult experts from health and medical area to verify the rationality of the indexes for evaluating health service spatial accessibility; consult experts from mathematics to verify the functional relations and the formulas; consult experts from cartography, geography and geographic information systems area to verify the technologies and methods related to the calculation of the indexes and the visualization of the spatial accessibility.(3) Data simulation test. In order to analyzing the advantages and shortcomings of the spatial accessibility methods and test the effect of visualization, we will take Shanghai for example to calculate the indexes for spatial access to medical services and make related maps. During the process of implementing these methods, we can verify and modify the methods and the technologies related to the visualization.4. Research Results(1) Evaluating spatial accessibility of medical service by minimum distance method. The basic approach of using minimum distance method to evaluate spatial accessibility of medical service was formed; the method of calculating the distance based on the real road network and the specific steps to calculate the index were summarized, and finally the distribution map of medical service’spatial accessibility of Shanghai using the minimum distance method was made. Then the advantages and shortcomings of minimum distance method were analyzed. Its advantages included direct and easy to understand. Its shortcomings included that it assumed people always chose the nearest medical institution, which apparently not coincided with reality. And it merely considered the distance factor among a number of factors which affected the convenience of residents’ access to medical services. Conditions such as number of patients far exceed that of doctors and the waiting time became longer was not convenient, while the factor related to the number of doctors and patients had not been considered. The ratio method and 2-step floating method could make up the shortcoming.(2) Evaluating spatial accessibility of medical service by the ratio method. The basic approach of using the ratio method to evaluate spatial accessibility of medical service was formed, the specific steps to calculate the index were summarized, and finally the distribution maps of medical service’spatial accessibility of Shanghai on county and town level using the ratio method were made. Then the advantages and shortcomings of the ratio method were analyzed. Its advantages included direct and easy to understand, the same as the minimum distance method. The first shortcoming was that the method restricted the medical resources by the administrative division, which assumed that the medical resources in one administrative area could only be used by the residents there, which was unreliable. The second shortcoming was that the method was unable to show the differences of spatial accessibility degree within the administrative divisions. The 2-step floating method can make up these shortcomings.(3) Evaluating spatial accessibility of medical service by the 2-step floating method. The basic approach of using the 2-step floating method to evaluate spatial accessibility of medical service was formed, the specific steps to calculate the index were summarized, and finally the distribution map of spatial accessibility of Shanghai was made. Then the advantages and shortcomings of the 2-step floating method were analyzed. Showing the differences of spatial accessibility degree of difference region within the administrative division was its most important advantage. And, the shortcoming was that it had to define a threshold distance first and the definition was so difficult. It assumed that only the medical resources within the threshold could be utilized by the residents and those medical resources had the same effect on the residents’spatial accessibility no matter how far the medical resources were located from the residential districts. While, the fact was that the effect would decay with the distance from the residential points to medical resources becoming farther. The gravity method could make up the shortcoming.(4) Evaluating spatial accessibility of medical service by the gravity method. The basic approach of using gravity method to evaluate spatial accessibility of medical service was formed, the specific steps to calculate the index were summarized, and finally the distribution map of medical service’spatial accessibility of Shanghai was made. Then the advantages and shortcomings of the gravity method were analyzed. Showing the differences of spatial accessibility degree of difference region within the administrative division and not needing to define a threshold distance were the most two important advantages. And, its first shortcoming was that it had to define a parameter β while the definition was difficult. Its second shortcoming was that the index of gravity method was not an index which reflected the location’s own property, which mean it could only be used to comparing the differences among different locations within a certain area and had no actual meaning.(5) Empirical study on the value for parameter β. The value of parameter β was one of the shortcomings of gravity method. We formed the basic approach of determining the value of parameter β. And using the data of inpatients from one of the three-grade comprehensive hospitals and one of the two-grade comprehensive hospitals, we estimated the parameter β values for these two types of hospital respectively, which was 0.67 and 1.57.(6) A method to expressed spatial accessibility developed by ourselves, which were named "resource allocation method". In order to make up the second shortcoming of gravity method which was the index of the gravity method having no actual meaning, we explored a new method based on the essential thought of gravity method which was the degree of spatial accessibility was decaying along with the distance increasing. The index of "resource allocation method" was the amount of the medical resources per thousand populations and its formula was And we tested the rationality of the formula. Firstly, the sum of the index value for every residential points multiplied by the number of population was equal to the number of the medical resources in all. |
PDF Full Text Request