Ending affirmative action hurt educational and wage attainments for Black and Latino students and worsened socioeconomic inequality, find a new study from UC Berkeley’s Center for Studies in Higher Education.

The study analyzes Proposition 209, which banned affirmative action at California public universities in 1998. Using a highly-detailed, anonymized database of every California high school senior who applied to any University of California campus between 1994 and 2002, and linking those individuals to a wide range of later-life outcomes like degree completion and annual wages over 15 years, the study transparently measures the impact of Prop 209 on Black and Hispanic applicants in the years before and after Prop 209, compared to their white and Asian peers.

Zachary Bleemer, the study’s author, shows that ending affirmative action caused UC's 10,000 annual underrepresented minority (URM) freshman applicants to cascade into lower-quality public and private universities. URM applicants' undergraduate and graduate degree attainment declined overall and in STEM fields, especially among lower-testing applicants. As a result, the average URM UC applicant's wages declined by 5 percent annually between ages 24 and 34, almost wholly driven by declines among Hispanic applicants. By the mid-2010s, Prop 209 had caused a cumulative decline in the number of early-career URM Californians earning over $100,000 by at least 700 people, or 3 percent. 

Prop 209 also deterred thousands of qualified URM students from even applying to any UC campus. Despite the expectations of many, enrolling at less-selective UC campuses did not improve URM students' performance or persistence in STEM course sequences; URM UC students earned lower grades than their non-URM peers as a result of poorer high school opportunity and preparedness, not affirmative action. The study provides evidence that affirmative action's net wage benefits for URM applicants exceed its (potentially small) net costs for on-the-margin white and Asian applicants. In other words, it appears that the URM students who were no longer able to enroll at their preferred UC campus after Prop 209 would have benefited more from UC enrollment than those who took their places.

”University affirmative action policies are highly controversial,” Bleemer said. “This study answers many of the key questions at the base of that controversy. If you don’t support affirmative action because you think it might not help targeted Black and Hispanic students, this study should make you rethink your beliefs.”

Some previous research has suggested that affirmative action may harm Black and Hispanic students, perhaps by leading them to enroll at more-competitive universities where they would have a difficult time keeping up with their peers. Bleemer’s study is inconsistent with this university “Mismatch Hypothesis,” and uses its newly-collected data sources to show that previous studies that defended “mismatch” do not stand up to careful scrutiny. In short, this new study provides the first causal evidence that banning affirmative action exacerbates socioeconomic inequities.