The other factor that affect very deeply the rising of inequality was the decline of unions and education. Research has shown that unions' ability to reduce income disparities among members outweighed other factors and its net effect has been to reduce national income inequality [3] [4]. The decline of unions has hurt this leveling effect among men, and one economist (Berkeley economist David Card) estimating about 15–20% of the "Great Divergence" among that gender is the result of declining unionization. As stated above one of the presidents who caused a very major change was Ronald Regan who eliminated most of the unions that existed in the United States. Taking the only voice that every company used to have to defend the rights of the employers.
