In Congress, working-class backgrounds matter (UC Berkeley study from 2015)
I think that this is fairly obvious intuitively, but it's nice to see some empirical evidence in support of it.
Members of Congress with working-class childhoods especially Democrats are more likely to cast roll-call votes for policies expanding opportunities for low-income families in health care, food aid, the minimum wage and higher education.
Findings from the study, conducted by Jacob Grumbach, a doctoral candidate in the Department of Political Science and a graduate fellow at Berkeleys Institute of Governmental Studies, are summarized in the June edition of Political Research Quarterly. His complete analysis, Does the American Dream Matter for Members of Congress? Social-Class Backgrounds and Roll-Call Votes, is online.
Having a working-class background tends to make members of Congress (especially Democrats) more liberal, explained Grumbach. There are other factors that make legislators more liberal, too, such as coming from a district with liberal voters, or being nonwhite or female but coming from a working-class background is especially impactful.
Grumbach noted that almost all members of Congress are upper-class and held elite occupations before being elected to seats in Washington, D.C.
Grumbach noted that few Republicans with working-class experiences get elected to public office, and upper-class Republicans in Congress do not back government support programs for the working class as often as Democrats even if they did grow up in families of modest financial circumstances.
http://news.berkeley.edu/2015/07/22/study-shows-how-working-class-backgrounds-affect-congressional-votes/