本研究主要的目的在透過分類與迴歸樹（CART）分析方法，探討中學生在不同學習階段的學習成就情形及其相關因素，比較不同學習階段中學生之學習成就相關因素的差異，並進一步建立不同學習階段學習成就高低的分類預測模型。本研究以臺灣教育長期追蹤資料庫（TEPS）為資料來源，採用第一波國中樣本和第三波高中/高職/五專追蹤樣本學生和家長問卷，樣本數為3022人。研究發現：（1）中學生於不同學習階段的學習成就有顯著差異，高中/高職/五專階段的學習成就表現高於國中階段；（2）中學生於不同學習階段的學習成就相關因素是有差異的。國中階段的CART 分類模型包括11 個變項，涵括了個人、家庭和社會網絡三個因素，高中/高職/五專階段的CART 分類模型，包括課程類別和學校公私立別兩個變項，包括了個人和學校兩個因素；（3）中學生於不同學習階段，用來區分學習成就高低的因素有差異。

The purpose of this study was to, through Classification and Regression Trees (CART) analysis, investigate and compare leaning achievements and relevant factors among high school students at different academic levels, and then establish a classification model that can predict different levels of learning achievement with different academic levels of high schoolstudents. This longitudinal study utilized the database of Taiwan Education Panel Survey, adopting waveⅠand wave Ⅲ questionnaires filled out by one selected group of students and their parents. The total sample consisted of 3022 students who were in junior high school at waveⅠand followed up when they were senior high school/vocational high school/junior college students at wave Ⅲ. The three major findings of this study are: (a) The learning achievements of high school student at different academic levels were significantly different. The learning achievements of senior high school/vocational high school/junior college students were better than that of junior high school students; (b) The factors related to learningachievement at different academic levels of high school students were different. The CART classification model for junior high school stage included three factors -- individual, family, and social network, within which 11 variables emerged. Another model for senior high school/vocational high school/junior college stage included two factors -- individual andschool, in which were two variables, course type and public or private school; (c) The factors that discriminated levels of learning achievement at different academic levels of high school students varied.