Korea has long debated whether the reputation of high schools unfairly affects college admission. In college admission, noisy measures such as high school GPA and a list of (non-)curricular activities are only observable. The reputation of high school enables colleges to make inferences about unobserved student ability at an extremely low cost. Elite high schools have the advantage of developing their students' learning abilities through outstanding activities more than regular high schools. Therefore, both elite high schools and their students send their high school background to colleges for successful admission. Although students from elite high schools have a lower high school GPA than students from regular high schools, they have more change to admitting to elite colleges. In this context, there is a demand for a blind admission policy to address the unfairness of college admission unfairness. This study finds the halo effect in college admission using the 2010–2017 Graduates Occupational Mobility Survey in Korea. The halo effect increases the probability that students from elite high schools enter elite colleges by 7.9%. The Halo effect is stronger in families in which the father's education or family income is lower. Following Rajabi and Garibay (2022) and Lee and Song (2022), we conduct a simulation study using machine learning to construct a synthetic dataset that mitigates the halo effect using a blind admission policy. The synthetic dataset satisfies the assumption that elite and regular high school students have equal chances of admitting to elite colleges. The finding that the halo effect disappears regardless of family background implies that the blind admission policy will no longer distort admission outcomes and that underprivileged families will not need to make unnecessary sacrifices to benefit from it. By enhancing the blind admission policy, fairness in college admission can be achieved at a low cost.