| Summary: | 臺灣各縣市人口結構差異明顯，各縣市的人口出生、老化程度都不盡相同，而且在醫療分配及社會資源的使用也有很大的差異，因此各縣市應因應各地特性發展不同的小區域人口推估方法。由於樣本數與變異數成反比，人數較少者的死亡率（像是高齡人口）通常震盪較大，藉由適當的修勻(Graduation)調整，通常可降低年齡層間的死亡率震盪。然而，當縣市層級的人數太少時，只依賴修勻往往不足，多半會再參考人口較多的大母體之死亡率。例如：傳統的的貝氏修勻，使用Lee-Carter之類的參數死亡模型(Lee and Carter, 1992)，或是透過小區域及大母體的死亡率比值（王信忠, 2012）。然而過去研究較少全面性的比較這些方法，尤其是用於人數較少（如：十萬人）的地區。
本文以探討小區域生命表及死亡率推估為目標，著眼於人數不多於五萬人，尋求較為適合臺灣及類似國家的死亡率編算方法。由於修勻或貝氏等方法可視為增加樣本數，本文將擴大樣本分為四種方式：「同地同時」、「同地異時」、「異地同時」、「異地異時」，亦即將死亡資料的整併分成是否限定於小區域，以及是否可擴及其他年度。本文藉由電腦模擬測試，提供在各種限制之下，最合適小區域生命表建構的準則。其中，本文假設大、小區域的死亡率間存有三種情境的關係：定值、遞增、V字型，藉由調整大小區域死亡率比值間的幅度，探討大母體及小區域間的差異對實務使用的影響。研究發現，Partial SMR方法是一個值得參考的方法，當大小區域死亡率類型接近時的效果不錯，甚至可用於人數小於一萬人，但若死亡率類型差異過大，修勻方法會有限制，使用時需格外謹慎。 === The population structure, life expectancy (and age-specific mortality rates), and the speed of population aging vary a lot in different county of Taiwan. Each county has its own policy planning according to the needs. However, the county level population is usually not enough to provide stable estimates, such as of the life expectancies and mortality rates at the county level. Thus, certain graduation methods are applied to stabilize these estimates. However, only a few studies focus on comparing different types of graduation methods, including traditional graduation methods, Bayesian methods, and parametric mortality models.
In this study, we separate the graduation methods into four types, according to if using only the small area data and if one year or multiple years of data are used, and explore which methods are appropriate to the areas with population fewer than 100,000. We use computer simulation to evaluate the graduation methods. We found that the Standard Mortality Ratio is promising when the mortality profiles of small and large populations are similar, and it is a feasible solution even for the areas with population fewer than 10,000. However, if the mortality profiles differ significantly, all graduation methods need to be applied with care.
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