“It turns out that poverty and family structure are intertwined in this country,” Professor Melissa Kearney of the University of Maryland told Freakonomic’s Stephen Dubner. “You can’t be interested in children’s well-being and not look at family structure.”

Over 40 per cent of US births and 35 per cent in Australia are to unmarried mothers. But there’s been a big change.

“It turns out that in 1960 only five per cent of births in the US were to unmarried mothers,” says Kearney. Marriage in the US has declined mostly amongst less educated sections of the population. This big change has its victims: “The kids born to less-educated single mothers are falling further and further behind.”

“Fewer than ten per cent of births to women with a college degree are outside marriage,” says Kearney. The figure for those with a high school certificate or less is 60 per cent.

Freakonomics points out that decades of socio-economic research has confirmed many times that there is a link between family structure and economic outcomes. It is sadly no surprise.

According to Kearney, kids living with two married parents have:

• Lower rates of poverty
• Higher cognitive test scores in childhood
• More likely to complete College /University
• Fewer behavioural problems
• Better health outcomes, and
• Less likely to become young unmarried parents themselves

In the US, race complicates the figures. Over 70 per cent of births to African-American mothers are to unmarried women. Freakonomics points out that the 60’s stereotype of single teenager mother living with her mother has broadened to include a white group of mothers co-habiting with the child’s father.

“But the most powerful predictor of single motherhood is still the level of education,” says Dubner.

“Fewer than ten per cent of births to women with a college degree are outside marriage,” says Kearney. The figure for those with a high school certificate or less is 60 per cent.

The liberal lefty Freakonomics team acknowledge that “many” (meaning their audience – the podcast comes from New York Public Radio) are uncomfortable prescribing marriage as a solution. But both Dubner and Kearney are married with children.

But the “marriage bonus” is in the figures.

“I know a lot of academics don’t want to see that because it sounds very social conservative and preachy. But if you think about how highly educated parents are behaving, they are almost entirely having children inside of marriage.”

She explains that the kids who get investments of time and money from two parents are doing extremely well. Kids of single parents with less education are falling behind. “To not be honest about that is not doing anybody any favours, even if it is politically more comfortable.”

…for the first time there is evidence that marriage in a Western culture is driven not merely by the economy but by what people believe … at least about marriage.

Freakonomics goes on to ask an awkward question. What has caused the precipitate fall in the marriage rate (especially among poor people) – was it a lack of economic opportunity (the lefty-liberal option) or the breakdown of social norms (the social conservative explanation)?

Eternity reported on the effects of economic slowdown on men and a key book about it, The Death of Men, here. The lack of steady employment for the men who used to work in factories in Western countries is held to be part of the unmarried birth spike.

Kearney has been looking recently at the effects of the US’ “fracking boom” in some states which has led to an improvement in the job prospects for less educated men. (Fracking is a method of extracting gas. It’s been resisted in many parts of Australia, especially by farmers.)

It’s a great test case to see how economic conditions affect family structures. She looked at states where fracking provided opportunity to settled populations, rather than FIFO (fly-in-fly-out) workers.

A decline in church attendance and Christian belief accompanies the decline in the marriage rate in Western societies.

Kearney found that the better jobs situation in fracking states saw “no increase in marriage … despite an increase in marriageable men.” But there were more babies.

In the similar coal boom of the 1970 and 80s there was an increase in marriage. This time, same sort of people, similar sort of boom, no increase in marriage.

The earlier coal boom saw marriage increase and fertility increase but very few kids born outside of marriage. The recent fracking boom saw no increase in marriage but a similar number of kids born, but who were born outside of marriage.

The conclusion? “Social context is really important to the response to economic changes.” Or to put it simply, the view of marriage had changed.

“Correlation is not causation.” Absolutely. But this might just be the exception.

So, for the first time there is evidence that marriage in a Western culture is driven not merely by the economy but by what people believe. At least about marriage.

This is not to say that whether the economy is doing well or badly has no effect on marriage.

I know that – my parents delayed their marriage for years because of the effects of the Great Depression – they spent the money they had saved to aid family members.

But Kearney’s case study provides evidence that a shift in what people think about marriage has been pivotal to the massive decline in marriage by less educated people, at least in the United States.

Many Christians will also note that a decline in church attendance and Christian belief accompanies the decline in the marriage rate in Western societies. The 2016 census shows 52 per cent of Australians reporting a Christian belief in 2016, down from 87 per cent in 1961.  In Australia the marriage rate for persons over 15 was 64 per cent in 1961, and 39 per cent in 2016.

Just about now at least one reader will be thinking “correlation is not causation.” Absolutely. But this might just be the exception.