Constructs Embedded in the National Achievement Test Results of the Philippines

This study aimed to determine the constructs rooted in the National Achievement Test (NAT) in the country. The data of the NAT performance of Grades 6 and 10 in four subjects namely Filipino, Science, English and Mathematics of the sixteen regions in the country in the year 2009-2015 were subjected to Principal Component Analysis. The study revealed that a commonality exists between Science, English and Mathematics performance of the learners. It manifested Technical-Instructional Language Index i. e. , English as the medium of instruction used in teaching Science and Mathematics is a significant factor that provides empirical measures or information on the learners capability in terms of their logical or critical reasoning skill. Non-Instructional Language Index was also established which shows that Filipino subject has nothing to do with Science and Mathematics instructions. However, the inclusion of Filipino subject in the National Achievement Test is relevant unless it is used as a medium of instruction in some other subjects. Hence, the medium of instruction is one of the most important factors that could affect the learning of the students.