The past few years have seen a shift in many universities' admission policies from test-required to either test-optional or test-blind. This paper uses laboratory experiments to examine students' reporting behavior given their application package and the school's interpretation of non-reported standardized test scores. We find that voluntary disclosure is incomplete and selective, supporting the incentives of both partial unraveling and reverse unraveling. Subjects exhibit some ability to learn about the hidden school interpretation, though their learning is imperfect. Using a structural model of student reporting behavior, we simulate the potential tradeoff between academic preparedness and diversity in a school's admission cohort. We find that, if students have perfect information about the school's interpretation of non-reporting, test-blind is the worst and test-required is the best in both dimensions, while test-optional lies between the two extremes. When students do not have perfect information, some test-optional policies can generate more diversity than test-required, because some students with better observable attributes may underestimate the penalty on their non-reporting. This allows the school to admit more students that have worse observable attributes but report. We test the results' robustness to a variety of extensions. [Funding for this report was provided by University of Maryland College of Behavioral and Social Sciences.]