[This commentary first appeared in The Portland Tribune]

Chants of “equal pay” filled the stadium after the U.S. women’s national soccer team clinched its fourth World Cup title. Despite their unparalleled record, these elite female athletes earn hundreds of thousands of dollars less than their male counterparts for their work on the national team. This may change as a result of a lawsuit filed by members of the women’s team against the U.S. Soccer Federation that alleges gender-based pay discrimination.

While the U.S. women’s soccer players have grabbed the attention of the world, other lesser-known but important fights for equal pay are also taking place. Here in Oregon, women working for Fred Meyer are taking action to demand equal pay. According to UFCW Local 555, Fred Meyer uses arbitrary employment categories that lead to women being paid significantly less money for substantially the same work as their male colleagues. The company insists that there’s no gender-bias in the job classifications, but Portland-area members of the union have voted to authorize a strike in protest of low and unequal wages.

Their situations may be different, but what these world champion soccer players and grocery store employees have in common is taking collective action to fight to close the pay gap for everyone. One of the most effective ways to reduce or eliminate the gender pay gap is quite simple: join a union.

For years women have gotten advice on confronting the pay gap that hinges on individual action. “Lean in” to get ahead, counseled Facebook’s Sheryl Sandberg in her best-selling book by that name. She argued that one of the biggest obstacles to women’s success is a lack of self-confidence and drive that leads to an alleged “ambition gap.”

That story, however, doesn’t stand up to scrutiny. A new study shows that when women do “lean in” and ask for a raise, they are more likely to be told “no” than their male colleagues. Placing the burden for closing the wage gap solely on the shoulders of individual women is a losing strategy.

When women band together through unions, on the other hand, the pay gap nearly disappears. In Oregon, the typical woman over the age of 16 working full-time year-round earns just 81 cents for every dollar that a similar man makes. That’s a difference of nearly $10,000 in a single year. For many women of color the picture is even worse: Black women in Oregon make 70 cents for every dollar a man earns, and for a Latina that figure drops to 55 cents.

Unionized women in the U.S., by contrast, earn 94 cents on the dollar compared to their male union colleagues. This is a drastic reduction in the pay gap. This bears out for Oregon workers as well. A study by the Oregon Center for Public Policy found that female public school teachers earn the same as their male colleagues. Public school teachers, of course, belong to a union.

Unions are effective in combating the pay gap for multiple reasons. They indirectly reduce the inequity by bargaining for uniform wages for classifications of workers, which removes a source of bias from pay decisions. Additionally, as is the case of UCFW Local 555, unions can directly fight against pay inequities they uncover through the transparency provided by the collective bargaining process.

By reducing or eliminating the pay gap, unions can have a dramatic impact on a woman’s earnings throughout her life. Over the length of a career, a typical woman in Oregon loses out on nearly $450,000 in earnings compared to a man. That doesn’t even count the losses that underpaid women suffer due to decreased Social Security or retirement contributions resulting from their lower wages.

It’s nearly impossible to score a goal in soccer without a team working together. Likewise, if we are to win the fight against gender pay discrimination, we need to work as a team. We need to lean into a union.