In her most recent stand-up special, Hard Knock Wife[1], comedian Ali Wong describes one of the most tangible ways her life has changed since rising to prominence last year.

“Now I make a lot more money than my husband,” she tells the crowd. “My mom is very concerned that he is going to leave me out of intimidation. I had to explain to her that the only kind of man that would leave a woman who makes more money is the kind of man that doesn’t like free money.”

The joke’s warm reception highlights an awkward reality: It’s increasingly common for wives to make more than their husbands — about 38%[2] of wives earned more than their husbands in 2015, according to the Bureau of Labor Statistics — and it’s also common for that to make people uncomfortable.

New research suggests that even the couples themselves haven’t totally come around to the idea psychologically. And that could be influencing the way we understand inequality between genders.

When these couples report their income to the U.S. Census Bureau they tend to minimize the gap between their earnings by providing inaccurate information about their salaries, according to a study published earlier this year[3] and blogged this week[4] by the Census Bureau. When a wife makes more than her husband, the income the couple reports for the wife is 1.5 percentage points lower on average than her actual income. The income the household reports for her husband is 2.9 percentage points higher.

The study, which compared Census survey responses to tax data, found that couples will minimize the earnings gap between husband and wife regardless of whether the person answering the survey’s questions is the husband or the wife. The pattern doesn’t hold in couples where the husband earns more than his wife, the study found.

The findings indicate that even as a large share — about 40%[5] — of households have a female breadwinner, there’s still societal discomfort around the idea. The study also suggests that the data we use to understand this phenomenon, which is largely based on surveys, may be skewed.

“We would like to figure out how many women are earning more than their husbands, but because there are social tensions around that, that actually influences the data,” said Betsey Stevenson, a public policy professor at the University of Michigan and an Obama-era member of the White House Council of Economic Advisors.

There’s other evidence to indicate husbands and wives take steps to avoid a situation where a wife outearns her husband. A study published in the Quarterly Journal of Economics in 2015[6] found that wives are more likely to earn a little bit less than half of a couple’s combined income, than they are to earn a little bit more than half.

The researchers posit that this...

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