A study released on Friday, noting the gains made by black union workers in New York City, said that raising the rate of unionization among black workers across the country would help narrow the racial pay gap.
The study, conducted by two professors affiliated with the Murphy Institute for Worker Education and Labor Studies at the City University of New York, which issued the report, described high unionization rates for black workers who live in the city compared with national rates.
Nearly 40 percent of black workers who are city residents are union members, compared with roughly 13 percent of black workers nationally.
The difference between the rates of black and nonblack unionization is also especially pronounced in New York City. The black unionization rate is nearly double that of nonblacks in the city, a difference that is much smaller nationally.
The authors, Ruth Milkman and Stephanie Luce, found that black union members enjoyed higher wages than black nonunion workers, and were also likely to have better access to employer-sponsored health care benefits and pensions.
“Unionism offers black workers a substantial economic advantage in regard to earnings — to a greater degree than is the case for nonblacks, reflecting the fact that larger numbers of blacks than nonblacks are employed in low-wage jobs,” the study said.
Unionization shrunk the racial wage gap by roughly half, reflecting the tendency of unions to fight for more equal wage distribution across the workplace. Black nonunion workers who live in the city made about $4 less in median hourly earnings than their nonblack counterparts. Among union members, that difference dropped to $2.
Dr. Milkman, a sociology professor, said in an interview that the findings suggested one path to addressing racial disparities in pay and broader income inequality that have come under increasing scrutiny across the country.
“When unions were more powerful in the United States, income inequality was also smaller,” she said. “One component of that is de-unionization.”
She added, referring to the black unionization rate in New York City, “We knew it was better here, but the extent of that is surprising to even us.”
Dr. Milkman said the findings could be explained in part by the fact that the health care and transit industries, which are major parts of the city’s work force and have high proportions of black workers, are heavily unionized.
The study also found that the share of working city residents who identified themselves as union members continued to rebound, after concern swelled several years ago about the steady erosion of union influence in the city. One in four workers residing in the city were union members over an 18-month period from last year to this year, up from roughly one in five in 2012.