March 25, 2013

Intergenerational inequality

The United States has surprisingly low social mobility: in every country, the children of the rich are more likely to be rich than the children of the poor, but the US is even worse than most Western countries.

Felix Salmon links to some graphs by Evan Soltas, looking at mobility in terms of education, with data from the US General Social Survey. He finds that people whose fathers did not go to university are much less likely to go to university themselves (unsurprising), and that this is true at all levels of income (more interesting).

I’ve repeated what Soltas did, but smoothing[1] the relationships to remove the visual noise, and also restricting to people aged 25-40 (rather than 18+)

ineq

 

In each panel, black is less than high school, dark red is high school, light brown is university or junior college and yellow is postgraduate. These are plotted by family income (in inflation-adjusted US dollars).  The left panel is for people whose fathers had at least a junior college degree; the right is those whose fathers didn’t.

The difference is striking, and as Soltas says, may imply a greater long-term value for encouraging education than people had thought.

 

[1] For people who want the technical details:  A sampling-weighted local-linear smoother using a Gaussian kernel with bandwidth $10000, ie, svysmooth() in the R survey package. Bandwidth chosen using the ‘Goldilocks’ method[2]

[2] What? $3000 is too wiggly, $30000 is too smooth, $10000 is just right.

avatar

Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »

Comments

  • avatar

    Importance of education, sure. But there is a big intelligence heritability confound floating around in there too.

    2 years ago Reply

    • avatar
      Thomas Lumley

      I don’t think the intelligence confound is that strong. If you believe the genome-wide estimates from Peter Visscher’s group, the heritability of simple cognitive performance measures is about 50%, half of which would be from the father

      Assortative mating will bring this up a bit, but ont he other hand there are presumably also contributions of intelligence to income not mediated by education, and these won’t show up in this comparison.

      2 years ago Reply

  • avatar

    The children are also learning from their parents’ experiences. Education, particularly graduate education, is expensive in foregone earnings. At low parental income levels (x-axis), it isn’t clear that the effort was worth it. Children think, ‘why should I bother?’ So, fewer get degrees (y-axis).

    2 years ago Reply

    • avatar
      Robyn Gandell

      I thought mother’s education was shown to be a better predictor of education achievement.

      And Intelligence? Is this a social construct to hide socio-economic and cultural advantage?

      2 years ago Reply

      • avatar
        Thomas Lumley

        I commented on intelligence already. It probably contributes, but it can’t explain the relationship — the heritability isn’t strong enough and intelligence presumably affects income.

        Mother’s education used to be a better socioeconomic status indicator, but if that’s still true, the relationship would be even stronger using mother’s education so I don’t see that it affects Soltas’ conclusions.

        2 years ago Reply

  • avatar

    Any doctor will tell you that Health is 80% nature and 20% nurture Education is about the same.

    Math/science graduates earn the most money because they are in short supply. Why? Because you need to be in the top 10% academically as determined by nature and work real hard in college which is the top 10%of the ambition curve. Those in the top 10% of both, if desired, make a lots of money.

    We have too many Psychology majors because you only need to be in the top 33% and little work s required. For the most part your parents determine nature.

    Don’t like poor people, blame nature for the bottom 2/3 of the IQ normal curve and nature plus nurture for the the bottom 2/3 in the ambition curve. Some are at the bottom of both and they are really poor. See http://www.textbooksfree.org/Interesting_Thoughts_Concerning_Education_Print.htm

    2 years ago Reply

Add a comment

First time commenting? Please use your real first name and surname and read the Comment Policy.