First thoughts on "The Son Also Rises"

 The main topic of the book is a study of last names. He looks at names that were, at some point in the history of a particular society, associated with a high or low status group, and then looks at data on professions and income over subsequent decades or centuries. He makes two points, one of which is inoffensive and the other of which is controversial:

1) While correlations between parental income and children's income can be surprisingly weak (suggesting that there's better mobility than we think/fear), if you look at names there's surprising persistence of certain families in high or low income tiers and elite professions. Nonetheless, the persistence decays, albeit much more slowly than the individual income data suggests.

He notes that the fact that there's a decay of correlation in this data does show a churn, and it's an exponential (Markovian) decay, strongly suggesting that it's hard to entrench certain advantages, but the decay is slow. This I agree with. The slow decay can be a problem from many perspectives, but the Markovian decay gives assurance that parents aren't destiny, that people can rise or fall. In a Markov process each step is a "reset", even if a rest with weighted probabilities.

He suggests that the correlations on single-generation time scales capture short-term random fluctuations, and ignore the longer-term effects, and that tracking names means it's easier to see long-term persistence. This is also reasonable. His attention to professions sheds light on some of this: Suppose that we look at a family of doctors, and a grandparent is a surgeon (high pay) while the next generation has a pediatrician (usually more modest pay), and the third generation has some high-paid specialist. This is a family that isn't leaving the upper tiers of society anytime soon, but a simple income analysis would show large fluctuations, even though those fluctuations are all within a comfortable tier.

Since names are usually patrilineal, a name analysis is leaving out half of the population, but if your goal is to understand control of resources then it's not completely inappropriate to focus your attention on the half of the population that has controlled and, sadly, largely still controls the most resources. Of course, it is still a significant limitation of the data set, and you have to be honest about that. But all real-world data on social phenomena comes with huge limitations, so as long as he is candid about this it's an acceptable study.

2) He argues that since this persistence shows up in many societies, both at the top and at the bottom, and across centuries (I've only read his analysis of Sweden so far), and since it remains unaffected even by major changes to economic conditions (e.g. it shows up both in egalitarian Scandinavia and cut-throat capitalist America), workers' rights, and educational systems, there's probably a genetic component.

This is obviously more controversial and less convincing, partly because parents pass on customs and ideas as much as DNA, and your childhood environment in any society depends on your class position.

Also, thus far his analysis of professions has been limited to law and medicine, two professions that have high barriers to entry (medicine especially). And the barriers have only risen as educational credentials have become more common. Once upon a time some people attended med school or law school without finishing an undergraduate degree. Now you see many people not only do a bachelor's degree but even a master's degree or a few years of carefully-chosen professional or community service experience to polish their applications. It's a lot easier to spend a few years studying for the MCAT and volunteering at community health clinics after college if you have affluent parents. But if your affluent parents are in some other profession, they might say "Why are you wasting your time so you can take out huge med school loans and then work for low pay as a resident? Just go get a job in my field!" It might be that you need a parent who's a doctor to see it as worthwhile to spend a few years further polishing your application.

I'll have to see what else he looks at besides medicine and law.