This paper addresses the intersection of testing and policy, situating test-driven impact and validation within the context of policy-led educational reform in Korea. I will briefly review the existing validation models. Then, arguing for an expansion of the conventional conceptualization of consequential validity research, I use Fairclough's dialectic-relational approach in critical discourse analysis (CDA), positioned in critical and poststructuralist research tradition, to evaluate social realities, such as intended and actual impact of policy-led testing, I take, as an example, the context of the development of the National English Ability Test (NEAT) in Korea, which had been used as a means of implementing government policies. Combining Messick's validity framework for consequential evidence, Bachman and Palmer's argument-based approach to validation (assessment use argument, AUA), and Fairclough's dialectic-relational approach, I will illustrate how the impact of policy-led testing is performed and interpreted as a sociopolitical and discursive phenomenon, constituted and enacted in and through "discourse." By revisiting the previous Faircloughian research works on NEAT's impact, I postulate that the discourses arguing for and against social impact acquire their meanings from dialectical standpoints.