Unions don’t just benefit their members. They benefit everyone. And when union membership is low, it hurts all working people. Just in time for Labor Day, the Economic Policy Institute released a study that shows how it’s better for everyone when unions are strong.

A new study looks at the benefits of unionization to nonunion working families.

It’s not news that wages have been in decline. Real wages are lower today than they were in the 1970s. This new report from EPI points to an often overlooked reason why: union decline.

“Unions have functioned to raise the wages of all workers, union and nonunion,” said Lawrence Mishel, EPI president. “The erosion of collective bargaining has clearly taken a huge toll on nonunion wages in the United States, and is a major factor in the wage stagnation of the last four decades.”

Wage stagnation and inequality are usually attributed to factors like globalization and technological change, which surely have played a role. But as the EPI authors note, so has the weakening of unions.

Other studies have looked at the relationship of unionization and economic mobility, including a report from the Center for American Progress that found children do better – even as adults – when they come from union households. And EPI previously found that everyone’s wages – union and nonunion alike – are higher in states without right-to-work laws.

This EPI study however, looks specifically at the benefit to nonunion members when unions are strong – and the lost wages when they are not. The authors found that union decline eroded wages for everyone at every education level, regardless of experience. It was just a matter of how much.

For private-sector men not in a union, weekly wages would be about 5 percent higher if unions were as strong today as they were in 1979, the report found. For someone working year-round, this translates to about $2,700 annually.

For nonunion men in the private sector without a bachelor’s degree or more, weekly wages would be about 8 percent higher. And for nonunion, private-sector men with a high school diploma or less, it’s 9 percent. It is this group, the non-college educated man, that is the most affected by the loss of union membership, stated the authors.

The effects for nonunion women are not as substantial, the report noted, because women were not as unionized in 1979. Weekly wages would be about 2 to 3 percent higher. Yet, the authors point out that the cumulative effects are still significant. For the almost 33 million women in the private sector, weekly pay would be $461 million more – and roughly $24 billion more a year – if unions had maintained their power.

Union erosion can explain a third of the growth in wage inequality for men and one-fifth for women, the authors stated, citing earlier research.

When unions are strong however, it’s not just wages that increase. Unions raise the bar for benefits and working conditions as well, forcing nonunion employers to compete by offering the same. And unions are often the force behind labor-friendly policies, something that benefits all working men and women.

“We conceive of unions as players in a broader ‘moral economy’ that help institute norms of fairness regarding pay, benefits, and worker treatment,” the report authors stated.

“It’s about respect and dignity on the job, and the ability to take care of your family. That’s what unions have always fought for,” said International President Lonnie R. Stephenson. “What’s good for union members is good for all working families.”