The traditional nuclear family with the male as the sole wage earner is one that is fast eroding. Indeed, American data already reveals that around 40% of American mothers earn more than their husbands, and it’s estimated that by 2030 more than half of the world’s wealth will be owned by women.

Of course, given the patriarchal nature of many societies, this is not a transition that is going smoothly, and research has shown that some women appear to sabotage themselves in order to earn less than their husbands.  Data has shown a considerable drop off when women begin to reach earning parity with their partner.  A recent paper from the University of Michigan explores the situation to try and understand what is going on.

“It looks like there’s something going on that’s related to this breadwinner norm—it could be coming from who’s marrying whom or wives doing some manipulation where they withdraw from the labor market a bit or don’t take that better job to avoid making more money than their husbands. But what our paper shows is this is actually just an anomaly driven by this little spike of people who are exactly at the 50% mark,” the authors explain.

Tipping point

The researchers honed in precisely on this 50% mark where women start to earn more than men and found a surprisingly large number of couples where both partners earn the same amount.  Indeed, when those couples were removed from the sample, the discontinuities just before and after the 50% figure vanished.

The researchers believe this is likely to be a statistical anomaly caused by those couples that earn the same income.  They suggest that their findings should cause us to caution against inferring any clear social norms from any observed differences in spousal incomes.

The findings emerged after the researchers used a sample of men and women chosen from the 2000 US Census.  The sample consisted solely of couples in which spouses earn positive earnings, with the sample also limited to couples in the 18-40 age range without children.  This provided nearly 110,000 couples and the data revealed that wives did typically earn less than their husbands.

The team then simulated what might happen if they randomly matched men and women from this sample into couples.  The simulation produced a distribution that was still much the same, with very few women out-earning men.

“It’s kind of a cautionary tale: you can’t just go look at the proportion of wives who are earning more than their husbands and conclude there’s some social norm that the wife shouldn’t earn more than her husband,” Lam said. “You also can’t look at what happens just above the 50% share, because the spike in couples with exactly 50% distorts the picture.  We’re not arguing that there isn’t a male breadwinner norm. We’re just arguing that this is not the kind of evidence to prove it.”