升學優惠政策為我國提供原住民、身心障礙學生此二類「外加生」積極性差別待遇的重要教育政策之一，其政策效益及相關影響因素值得透過實徵性研究加以探討。本研究為固定樣本貫時追蹤研究，透過描述性統計、重複測量變異數分析及多重比較，分析升學優惠政策成效，及就讀不同類型學校外加生學業成就改變情形。研究資料為中投就學區8所高級中等學校普通科104學年度3,531位入學學生（含73位外加生及3,458位一般生）104學年度之「教育會考總積點」及106學年度「學科能力測驗總級分」，以其中73位外加生為本研究之研究對象。研究結果如下：一、整體而言，升學優惠政策有助於提升外加生的學業成就；二、就提升學業成就的角度而言，就讀競爭程度過高的學校未必是外加生的最佳選項。

Preferential admission policy is one of the important education policies that practices positive discrimination for the two types of “extra quota students” - indigenous students and students with disabilities. The benefits of the policy and related influencing factors are worthy of discussion through empirical research. This is a panel study which analyzes the effectiveness of preferential admission policies and the changes in academic achievements of extra quota students in different types of schools through descriptive statistics, repeated measure ANOVA, and multiple comparisons. The research data is the total points of Comprehensive Assessment Program for Junior High School Students and General Scholastic Ability Test of the 3,531 enrolled general course students (including 73 extra quota students and 3,458 general students) of 104 academic years in 8 senior high schools of the Taichung-Nantou school district. The results of the study are as follows: 1. Overall, the preferential admission policies can improve the academic achievement of extra quota students; 2. From the perspective of improving academic achievement, schools with a high degree of competition may not be the best option for extra quota students.