Marriage is a causal agent of economic growth. It constitutes one-third to one-fourth1) of the human capital contribution of household heads to macro-economic growth (Chart 1).2) 3) Divorce removes this agent of economic growth.
A revolution occurred in marital practice in the United States (see Chart 2). Over the course of the 1960s and 1970s, the fraction of marriages that would eventually dissolve tripled for 30-year-olds and quadrupled for 40- and 50-year-olds. The rate of divorce has remained roughly constant since then, though marriage has become less frequent.4)
The effects of the increased divorced rates are shown in Chart 3 below. The population of single men (bottom, orange area) is approximately proportional to population size, as marriage rates had not yet plummeted during the graphed period. The intact married population of men (center, blue area) increasingly transitions into the divorced population of men (top, red area) as time goes on and the divorce revolution affects the U.S. population. Holding divorces to their 1950s transition rates (Chart 2) allows researchers to differentiate two populations: those men who would (still) be divorced under the old regime (red area above the black line) and those who experience divorce under the new regime (red area below the black line).5)
Chart 4 shows the causal effect of divorce for those men who experienced divorce because of the divorce revolution. For this group of “new” divorcés, the rate of income increase, a measure of productivity growth,6) changes. Their rate of productivity growth decreases to nearly half that of single, never-married men.7) 8) Since divorce was relatively uncommon in the 1950s, and because around half of marriages end in divorce now (Chart 2),9) 10) 11) it can be said that it is this “average man” whose productivity is causally affected by the divorce revolution.12)
As workers move from the married state to the divorced state they bring their productivity in the marketplace with them. It is clear that this productivity changes because there is a change in their income,13) which is the value the market is putting on that potentially changed productivity.14)
The divorce revolution has a perpetual effect on the productivity of heads of (broken) households (Chart 4). Henry Potrykus of the Marriage and Religion Research Institute developed a model based on a natural experiment to determine both the transitions of workers from singlehood, through marriage, and into now-common divorce, as well as the productivity effects (if any) of these transitions. This model quantitatively describes population flows between the sub-populations of single, intact married, and ever-divorced men that occurred between the decennial census. The model also tracks the incomes of these men, properly accounting for incomes ported between sub-populations as these men transition to different sub-populations. That is, these men “brought their incomes with them” as they transitioned between states in life. In this way we are able to accurately depict the income dynamics of these groups, as marriage and divorce affect them.
Chart 5 shows married men earn substantially more than single men, and more than divorced men. Some researchers hypothesize that this is due to a “selection effect”: Women may select higher earners as mates, although women may equally select more exciting and risk-prone men. Similarly, men who innately have higher human capital may be more marriage-prone, although high human capital men may equally well choose exciting, risky women. This seems to be statistically a closed problem for the U.S.15)
A natural experiment helps explain how marital status affects productivity. As Charts 4 and 6 show, the rate of change in earnings year over year are consistently higher for men in intact marriages than among single or ever-divorced men. It is remarkable that these differences in these rates of change (the distance between the lines in Charts 4 and 6) are more consistently constant than income growth itself: Note how in Chart 6 workers over their 40s and 50s experience wage stagnation (zero income growth) from 1970 to 1980, while the differential productivity of marrieds relative to the other classes of men stays essentially constant.16)
In this experiment, there are two groups of divorced men (depicted in Chart 3): those that would have divorced anyway, and “new” divorcés, a product of the divorce revolution. If these new divorced men were from a “least-productive sub-pool” within the sub-population of married men,17) the remaining (smaller group of) married men would exhibit an apparent productivity boost, as this “dross” of new divorced men would finally be removed from that sub-population of marrieds. But there is no change in the distance between the wage-growth curves as the country evolves and the divorce revolution plays out (Chart 4, Chart 3).18) As this boost to the upper curve is not seen in the census data (no change in distance between curves), this “dross” cannot exist.
Similarly, if the new divorced men maintained their old productivity growth, a “most productive sub-pool” within the sub-population of divorced men would see a productivity boost. These newly minted divorcés would now be contributing a higher level of productivity to the divorced sub-population’s productivity. Again, there is no change in the distance between the macro-economically relevant wage-growth curves as the country evolves and the divorce revolution plays out. As this boost to the lower curve is not seen in the census data (no change in the distance between curves), this more productive sub-pool cannot exist. Chart 7 summarizes this argument.19)
Pre-divorce, divorced men are not less productive than other married men. Post-divorce, these new divorcés are not more productive than those whose class they are entering. Divorced men become less productive through divorce (Chart 8 and 9).20)
The divorce revolution has undermined growth in the U.S. economy.21) Since marriage has a “remarkably large”22) accruing effect on a worker’s productivity, divorce eliminates this agent for growth. Besides for population effects originating in the 1960s and 1970s, there are no other consequences of policy change that have had a greater effect in slowing economic growth than the divorce revolution. Divorce, having now become acculturated, perpetually inhibits growth of the U.S. economy.23)