Feminist organizations and gender pay gap campaigners are once again peddling the statistically suspect claim that women are paid substantially less than men for the same work.

Tuesday, April 12, has been dubbed Equal Pay Day because this day allegedly represents how far into the year women have to work to make as much as their male counterparts.

From the American Association of University Women to the White House, senior figures in public life lament that women make just 79 cents on the dollar compared to men.

But there’s a major problem with the pay gap narrative — it’s a statistical delusion which doesn’t reflect the real life choices men and women make about work and life.

The 79 cents claim suffers from the assumption that women in the U.S. are being paid substantially less for the exact same work, in the same jobs, working the same hours, with the same productivity and taking the same amount of time off, etc.

When President Barack Obama waded into the debate in 2012 claiming women were paid 77 cents on the dollar for doing the same work as men, Politifact labeled his statement as “mostly false.”

Each year, economist after economist wearily takes to the keyboard to explain to pay gap fanatics that the gap has almost nothing to do with sexism and discrimination and that there are bigger factors at play.

The Hours Gap

One of the reasons why men as a whole earn more, on average than women, is that men work more hours than women. According to Mark Perry, economist and scholar at the American Enterprise Institute, the average man working full-time worked almost two more hours per week in 2014.

In the same year, women in full-time work were found to be two and a half times more likely to have shorter workweeks of 35 to 39 hours per week, according to the Bureau of Labor Statistics.

Children

One of the most obvious reasons why an earnings gap arises is because many women leave the workforce temporarily to have children. “Anything that leads you to want to have more time is going to be a large factor,” says Harvard economist Claudia Goldin.

Women who choose to have children and take time off work can suffer a significant hit in earning compared to their male peers. “But we also see large differences in where they are, in their job titles, and a lot of that occurs a year or two after a kid is born, and it occurs for women and not for men,” Goldin adds. “If anything, men tend to work somewhat harder.”

A study from the University of Massachusetts found that for each child a woman has their earnings decrease by 4 percent.

Career Choice

A large part of the apparent disparity between men and women’s pay is down to career choice. Men and women often choose very different careers with men going into higher risk, higher paying professions.

A Department of Labor study released in 2009, which reviewed upwards of 50 peer-reviewed papers, concluded the wage gap “may be almost entirely the result of individual choices being made by both male and female workers.”

“Women, more than men, show a demonstrated preference for lower risk occupations with greater workplace safety and comfort, and they are frequently willing to accept lower wages for the greater safety and reduced probability of work-related injury or death,” Perry argues.

In 2014, men made up 92.3 percent of workplace deaths. “Because men far outnumber women in the most dangerous, but higher-paying occupations that have the greatest probability of job-related injury or death,” says Perry.