目標：適當的資源評估，將影響資源配置的合理性。以往以行政區域每萬人口醫療資源作為評估醫療資源配置的依據之一，由於地理資訊系統能夠掌握複雜的空間變異與差異，本研究旨在比較不同的地理概念所呈現的地理可近性對醫療資源評估的影響。方法：本研究應用「二階段浮動可近區位法」的分析方法，提出兩種具備距離特質的地理可近性評估模式，以2007年台灣本島各鄉鎮的每萬人口西醫師數為例，比較衛生署「現行評估法」與本研究的模式評估結果之差異。結果：本研究的兩種模式與衛生署「現行評估法」的比較結果，其分布差異大且相關度不高（相關係數各為0.38及0.57）。在進行西醫師資源缺乏鄉鎮的判定部分，與健保局判定的結果一致性並不理想（kappa=0.141～0.231）。此外，「新模式」與「現行評估法」之比值在空間單元面積最大組（面積大於112平方公里）有最多的鄉鎮介於0.8－1.25之間，而同組中有最多的鄉鎮評估順位下降大於50名；以鄉鎮人口加總至較大的縣市或區域時，其差異程度降低。結論：本研究顯示具距離特質的地理可近性模式對於評估鄉鎮層次的醫師資源有重大的影響，若未詳加考量將可能導致醫療資源補助的錯置。（台灣衛誌2011；30（6）：558－572）

Objectives: An appropriate evaluation of the supply of and demand for physician resources is important for the allocation of medical resource. The current evaluation practice, the townshiplevel physician-to-population ratio, cannot capture the characteristics of cross-district movements of the population. The purpose of this study was to use a geographic information system to capture spatial variations in order to compare different methods of spatial accessibility in the evaluation of physician resources. Methods: This study proposed a geographically modified physician-topopulation ratio by using a two-step floating catchment area method which incorporated two different distance-decay functions to evaluate physician resources in Taiwan. These methods were also compared with current evaluation practices. Results: Results from the catchment area method that incorporated two distance-decay functions were different from the current evaluation practice of township level ratios (correlation coefficients were 0.37 and 0.58). The areas of physician shortage identified by these two methods were also different from current evaluation practices (kappa = 0.141-0.231); however, the differences among these methods decreased when township-level population and physician data were aggregated at the county or regional levels. Conclusions: Our significant findings showed that township-level resource allocations could be misplaced if cross-township accessibility were not incorporated in the evaluation models. (Taiwan J Public Health. 2011;30(6):558-572)

醫師人口比；地理可近性；地理修正醫師人口比；地理資訊系統；二階段浮動可近區位法

physician-to-population ratio; geographic accessibility; geographically modified physician-to-population ratio; geographic information system; Two-step floating catchment area method