There are plenty of assumptions and falsehoods being bandied about in the World Cup pay disparity discussion. Let's set the record straight. (AP)

There's a popular assumption that the men's World Cup must bring in more money for FIFA than the Women's World Cup. Not just more, but a lot more. Multiples more.

With that assumption, the vast disparity in prize money between men's and women's soccer teams is justified by simple math. FIFA's prize money for the men's World Cup is 13 times the amount for the women – a $400 million prize pool vs. $30 million – so, the assumption goes, revenue must be the reason for it.

The problem, however, is that there are no facts to support that assumption.

The most popular set of numbers used to make this claim came from a Forbes report that alleged the Women's World Cup generated just $131 million revenue while the men's World Cup generated $6 billion. What the Wall Street Journal found on Tuesday, however, is that those numbers were false.

The $131 million figure was actually expenses for the Women's World Cup, not revenue. Forbes' assistant managing editor Mike Ozanian read a chart wrong, and then told his readers bluntly: “The pay disparity is justified.” He has since removed his erroneous article but the misinformation has already spread far and wide.

That fake $131 million figure has been used to justify paying the women pennies on the dollar in the Chicago Tribune, the Baltimore Sun, Fox Sports, and others. It's been cited in ESPN, the Washington Post, and more. The link to the now-retracted Forbes article has been shared over and over on social media, mostly by people arguing the women should not be paid more. It was even used by U.S. Soccer in an already-misleading slideshow from lobbyists to Congress.

View photos Viewership of the FIFA Women's World Cup as opposed to the men's is a key issue here. (AP) More

For the people who oppose increasing the prize money for the Women's World Cup, the assumptions likely persist, even if told that $131 million number is fake. The men's World Cup still probably brings in way more money, the assumers will say.

But it's actually impossible to know. FIFA bundles its two biggest sources of revenue, broadcast rights and sponsorships, for all of its World Cup events. That means that the rights to broadcast the men's World Cup are bundled in a package that includes the Women's World Cup. Since the rights aren't sold separately, it's impossible to know the value derived from each event, which FIFA openly admits.

When FIFA claims it made $5.4 billion in revenue from the 2018 World Cup, FIFA is assuming that broadcasters and sponsors are paying primarily for the men's tournament, not the women's one or the youth ones. Whether that assumption is true or not apparently doesn't matter to FIFA, according to Tatjana Haenni, who worked at FIFA for 19 years.

“That's something never really analyzed,” Haenni said in March. “What is the potential value of the Women's World Cup? Nobody knows the Women's World Cup commercial value because it's not sold separately. This is something that should at least be discussed.”

The Women's World Cup clearly has some value, even if FIFA assigns all the value of its TV and commercial deals to the men's World Cup. Fox Sports bid $400 million for FIFA's broadcast rights, and David Neal, the head of the network's World Cup coverage, said he wasn't sure how he'd split the value between the men's and women's tournaments, but added: “Right now the shining star of U.S. Soccer is the U.S. women’s national team.”

The truth is, that multibillion revenue figure is not actually just for the men's World Cup – it's for all of FIFA's World Cup events in a cycle.

Still, for those who oppose higher prize money for the women, the assumption surely persists: If the pay disparity is not based on revenue, then it must be based on something else, like the men getting vastly higher television ratings, they will say.