Inequality, mobility, single mothers, and race: comment

I have no idea whether inequality increases intergenerational immobility. But I do know that lots of people would like to pin bad social trends on single motherhood, meaning — in their view — the bad decisions of people who already poor. And that has bad implications.

In a blog post by Scott Winship and Donald Schneider at the Manhattan Institute, they argue that the liberal argument that inequality blocks mobility is not well supported. To do that, they show simple bivariate correlations between single motherhood rates and immobility across U.S. labor markets. Their point is that, if you want to use that simple bivariate standard, you can just as well — but better — argue that immobility is caused by single motherhood rather than by income inequality, because the correlation is very strong. For their exercise they use data from the Equality of Opportunity Project, which is freely available here.

In a series of tweets, Winship clarified his point:

point wasn’t to highlight single parenthood—point was to show where low evidentiary standards on left can take you … look, single motherhood may very well be a big problem for mobility. Inequality might too…. but the left has to be held accountable when they make bad arguments skewing policy debates…  I clearly wrote that correlations shouldn’t constitute reason for getting worked up about single moms

I take him at his word on his intentions, but those with well-documented patterns of less scrupulous behavior are not so scrupulous, and so the post was bad. Despite a disclaimer about not reading causation from correlation, they also wrote:

In other words, a [labor market’s] prevalence of single motherhood predicts its relative mobility quite well all by itself. … the relationship between single motherhood and mobility holds up in all of these analyses. … On the basis of these charts, rather than a new Washington Center on Equitable Growth housed at CAP and devoted to discovering the damages that income inequality inflicts, the left should have started a Washington Center on Single Motherhood.

Again, my only dog in the fight is fighting against the easy right-wing causal association of single motherhood with bad outcomes. The Heritage Foundation, Scheider’s employer, is particularly egregious in this, as I’ve occasionally documented (here and here, e.g.)

So here’s a quick debunk on that. A simple glance at the map from the Equal Opportunity Project will tell you that race is involved here, but it didn’t come up in Winship and Schneider’s post:


So let’s just look at the relationship between immobility, single motherhood and race. (Immobility here is measured by the effect of family income on children’s incomes. Higher scores are bad.)

So first, here is the relationship between population percent Black and immobility for the 100 largest metro areas, with the larger ones shown as bigger dots:

pb-immobThat relationship is quite strong: the higher Black population proportions are strongly associated with immobility. But so is the single motherhood relationship, as Winship and Schneider reported. So, we turn to the obvious tool, a multivariate regression. Here are two models, the first with just single motherhood — in effect, the Winship and Schneider result — and then a model with proportion Black added. Both are weighted by population size.


This shows that the association between single motherhood rates and immobility is reduced by two-thirds, and is no longer significant at conventional levels, when percent Black is added to the model. That is: Percent Black statistically explains the relationship between single motherhood and intergenerational immobility across U.S. labor markets.

This is not a rigorous examination of the cause of intergenerational immobility. It is just debunking one bivariate story that is too easily picked up by the forces of bad.



9 thoughts on “Inequality, mobility, single mothers, and race: comment

  1. On the race front, this kind of table is subject to the critique that it seems to say that a person’s race somehow causes a negative outcome. So perhaps worth expanding on your point. Notice that adding race dramatically INCREASES the variance explained over single-motherhood only. This means, contra many pundits, that the race problem is not merely single motherhood, as the race effect remains strong when single motherhood is included. However, at the aggregate level, what this is saying is that the kinds of places that have lots of black residents are also the kinds of places that have higher immobility rates. Local political or economic policies that help or hinder mobility are the likely culprit, and such policies can vary with racial composition. Notice that the aggregate effects are not simple reflections of individual actions. Black people vote on the liberal/Democratic end of the scale, but places with higher Black population proportions (especially in the South) often exhibit more conservative aggregate voting/policy patterns, because the White voters in those places are often especially conservative.


  2. First, I am not a fan of Winship, Schneider, the Manhattan Institute or their ideological research. However, in the case at hand — do teen births decrease relative mobility — I find some support for their conclusion. Using Chetty’s dataset I created a new binary variable — Greater Relative Mobility — where 1 equals greater than the median relative mobility and 0 equals less than the median relative mobility for each commuter zone. Using that variable as a dependent variable and percent teen births and percent Black population as predictors, a logistic regression revealed a significant model with both predictors significant.

    My conclusion: Teen births and percent Blacks in labor markets jointly and independently impact the probability of achieving greater than median relative mobility. Percent Blacks appears to have a much greater adverse association with relative mobility.

    If interested, see:


    1. Interesting. Winship & Schneider, and I, used single mother families, not teen births. These are pretty-well but not perfectly correlated (.48). The obvious problem with teen births is that they are an outcome of poverty and thus perhaps low mobility. Also, small labor markets have outsized influence in this dataset unless you weight by population. (Note, e.g., the average labor market has 12% teen births, but the population-weighted average is 10%.)


      1. Actually, even less; only about 8% (305,000) teen child births in 2012, as compared to overall births of about 3.9 million. More up to date research (Melissa Kearney) shows that teen births are not correlated with poverty, but with income inequality. So showing intergenerational immobility correlation with percentage black and percentage single mothers, is probably better. When related to percentage teen mothers, we have to take inequality into consideration, and we will lose correlation from cause.


  3. I have another question for Dr. Cohen. The labor participation ratio has decreased systematically from close to 70% to 60% (see BLS data) ovr the last 20 years, while unmarried women with children has increased by 50%. Single women with children are hindered with mobility issues. Is the reduction in labor participation caused by significant increase in women having children outside wedlock, or I got the causation-correlation wrong,?


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