This study was conducted as a form of collaborative action research between a university professor of curriculum and two elementary teachers, examining the harmful effects of Seoul metropolitan school district\'s test-driven curriculum and instruction on teaching and learning. Using qualitative method, researchers examine the filtering process, adoption, and adaptation of test policy for high performance and how this high-stake test policy affects the practice of classroom level teaching and learning. Regardless of official direction of the policy which do not emphasize schoolwide test implementation with multiple choices questions, these tests turned out not to measure whether or not students can apply or actually use what they have learned to higher-oder problem solving. Instead, a number of teachers are forced to use test preparation teaching method for fear of comparison to other classroom\'s performance which is measured by whether a child is prepared to find out correct answer out of multiple choices and short answer rather than what is learned in depth in the more valuable, meaningful, and constructivist performance evaluation. Researchers suggest some implications from this research: first, a schoolwide test for the comparison purpose is not pedagogical as a policy means; second, teachers should keep parents informed in the form of meaningful exchange of students\' growth and learning. Even in this case, parents should be restrained from putting students in a over-heated competition which has been an long lasting issue in the Korean education .