This research aims to analyze the causes of failure in the policy of National English Ability Test(NEAT), which died off two years after the implementation despite the investment of the enormous budget of over 60 billion won, through the major concepts developed in the time lag approach. First, in the aspect of temporal relationships among cause variables, the NEAT policy was pushed for when there were no prerequisites fully prepared such as expansion of speaking and writing education in English education in schools which are needed for the NEAT policy to achieve effectiveness. Second, in terms of maturation, the NEAT policy was pursued without properly considering the maturation during which the measures for changes of English education in schools, which include revision of educational curriculum and enhancement of teachers' professionalism, could have effect, and the other maturation for teachers and students to adjust to the unfamiliar exam. Third, from the perspective of the institutional congruence, the administration and operation methods of the NEAT had limitations in bringing changes of school English education and improvement in students' communication skills, and did not agree with the environmental contexts of fairness and equity that college entrance examinations have. Fourth, in respect of time lag on recognition, there was a time lag for those concerned with the policy to perceive problems which were pointed out several times by press, public hearings, and research results, and to arrange countermeasures.