臺灣六都間人口遷移模型建構

Abstract

臺灣現今設籍於都會區內的人口數占總人口數超過七成，且都會區間的人口遷移也越發頻繁，民國112年間就有超過十九萬遷移人次，大量的人口遷移已然是各部門的重要議題，因此本研究試圖理解影響遷移吸引力之社會經濟因素，並建立符合臺灣都會區情境之人口遷移模型，藉以推估人口遷移之分配情形。本研究蒐集民國105至107年各都會區人口數與人口遷移矩陣資料，透過人口遷移的重力模型回推各都會區在均質無差異前提下之理論距離，並將其與實際距離之比值作為社會經濟因素差異所造成之遷移吸引力，再蒐集十七項社會經濟因素資料並利用主成分分析將其整合為三個社會經濟面相，透過簡單線性迴歸來建立人口遷移吸引力模型，並藉此調整原始重力模型中的距離參數，建立符合臺灣都會區情境之人口遷移重力模型。最後投入民國108年之資料推估人口遷移情形，並與實際情形進行比較。研究結果發現，臺灣都會區間社會經濟因素主要可以由「生活成本」、「生活機能」及「社會安全」三個面向來理解，其中「生活成本」及「生活機能」可顯著解釋約四成之人口遷移吸引力，生活成本越高則吸引力越小、生活機能越高則吸引力越大，並且生活機能之影響較大。此外，利用人口遷移吸引力所調整之重力模型有助於改善推估結果，而推估結果也與實際情形有相同趨勢，然而在桃園遷移至雙北及桃園遷移至高雄的低估情形最為嚴重、臺中遷移至桃園的高估情形最為嚴重，代表人口遷移吸引力仍然受其他因素所影響，是本研究無法解釋之處。Taiwan’s population registered in municipalities now accounts for more than 70% of the total population. Inter-municipality population migration also continues to increase, with 192,726 migrations recorded in 2023. This study aims to understand the socioeconomic factors influencing migration attractiveness and to develop a model suited to the context of Taiwan's municipalities to estimate the distribution of migration. This study collected data on population and migration matrices between municipalities from 2016 to 2018. Using the Gravity Model of migration, we back-calculated the theoretical distances between municipality pairs under the assumption of homogeneity. The ratio of theoretical distances to actual distances was used to represent the migration attractiveness caused by socioeconomic differences. Subsequently, data on 17 socioeconomic factors were gathered and integrated into three socioeconomic dimensions through Principal Component Analysis. A linear regression was employed to develop a migration attractiveness model, which was then used to adjust the distance parameter in the original gravity model. This adjustment tailored the gravity model to the context of Taiwan's municipalities. Finally, data from the 2019 were used to estimate the migration and compare it with the actual migration data. This study found that the socioeconomic factors affecting inter- municipality migration in Taiwan can be understood through three dimensions: cost of living, living amenities, and social security. Cost of living and living amenities significantly explained about 40% of migration attractiveness, with higher living costs reducing attractiveness and better living amenities increasing attractiveness, with the impact of living amenities being greater. In addition, the gravity model adjusted by migration attractiveness improved the estimation results, showing trends consistent with actual migration patterns. However, the model significantly underestimated migration from Taoyuan to Taipei and Taoyuan to Kaohsiung, while it significantly overestimated migration from Taichung to Taoyuan. This indicates that migration attractiveness is still influenced by other factors not explained in this study.