我國人口推計工作之評析與國際比較

Evaluation and International Comparison of Taiwan's Population Projections

為提升我國人口推計品質，本研究內容主要分為3部分，包括：（1）整理我國近年人口推計工作之重要內容，（2）分析我國歷次推計結果之MAPE誤差值，以及（3）分析13個國家或國際組織之最新人口推計報告。
研究發現歷次總人口及死亡推計數之MAPE誤差均小於10%，顯示預測能力極佳；歷次出生數之MAPE誤差均小於20%，顯示預測能力優良；而社會增加之MAPE誤差顯示其預測能力隨不同假設差異較大。由年齡別人口數之MAPE誤差，發現0歲及85歲以上人口之誤差較大；而年齡別生育率之MAPE誤差，則發現30歲以下之育齡婦女生育率誤差較大。此外，針對上述發現，以及藉由比較我國與世界人口推計工作之更新頻率、涵蓋期間及假設設定方法等重要推計工作內容，本研究提出對未來人口推計工作之數項建議。

The Council for Economic Planning and Development（CEPD）produces the official population projections for Taiwan biannually. This paper examines the performance of the series of population projections made by CEPD since1999. The paper also compares the methology, the assumptions and the framework of CEPD's population projections to those of 12 official population projections by other countries and international organizations.
The findings suggest that the CEPD's projections are fairly accurate on the total population, births, and deaths, but less accurate on the social increase of population over a short projection horizon. By calculating the age-specific errors, the largest differences between projected and actual populations are for the very young（age of 0）and the very old（over 85 years old）, and the largest differences between projected and actual fertility rate are for the women under the age of 30. By discussing who makes projections and how, and the key assumptions upon which they are based, this paper also provides a guide to other sources of demographic information, pointers to projection results, and an entry point to key literature in the field.