The study looked at how higher education affects income inequality in the United States from 1967 to 2015. They found that when higher education is limited, it can worsen income inequality. But when more people have access to higher education, it can help reduce the income gap. The researchers also looked at other factors like financialization, trade union density, and female labor participation, and how they impact income inequality. The results suggest that expanding education could help developing countries narrow their income gap.