The Connection Between Union Density and Income Inequality

Steven Greenhouse has a piece in the N.Y. Times on the connection between declining union density in the U.S. and increasing income inequality.  The piece describes a new study that asserts that declining union power and density, from 1973 to 2007, is responsible for a third on the rise in wage inequality among males (and a fifth for women).  The authors cite lack of union pressure as helping to keep wages down in both the union and nonunion sectors and less political interest in addressing wage inequality issues.  What's less clear (at least to someone who hasn't read the studyion only, which is subscript) is how much one can tease out the effects that union density has on wage equality versus other factors, such as technological advances and globalism, which affect both union density and wages.

Hat Tip:  Michael Duff

-JH