A new report out from the University of Oregon’s Labor Education and Research Center (LERC) attaches local numbers to something most people already know: Union workers have better pay and benefits than non-union workers. Looking at Oregon workers, LERC’s Lina Stepick and Mark Brenner analyzed statistics from the U.S. Census Bureau using a methodology developed by the UC Berkeley Center for Labor Research and Education.

They found that — all other things being equal — Oregon workers covered by a union contract earn 11 percent more than non-union workers, are 17.5 percent more likely to get health insurance through their job, and are 41 percent more likely to have an employer-provided retirement plan.

In dollar terms, they found that being covered by a union contract adds $4,701 per year to an Oregon worker’s annual income, on average. With close to 300,000 union members, that union differential could account for an additional $1.4 billion in income in the pockets of working Oregonians in 2017. And  that’s just the impact on members: Other research has demonstrated that unions also increase wages for nonunion workers, Stepick and Brenner note, particularly when they’re able to establish industry-wide standards for wages and benefits.

The report also found that union workplaces have a smaller gender pay gap. For Oregon, the gap between the average pay of men and women is 18.7 percent in non-union workplaces, but only 5.3 percent in unionized workplaces.

Wage differences between union and non-union, and between women and men, can be due to other factors, like differences in experience, education, and the industry in which they work. To isolate out the “union” effect, Stepick and Brenner controlled for those demographic and industrial characteristics using a statistical method known as regression analysis. The data came from the U.S. Census Bureau’s Current Population Survey, and they pooled data from 2011 to 2017 in order to ensure a sample size large enough for statistical analysis. In their sample, about 16.5 percent of workers were union members or covered by a union contract.