The Alchemy of Job Transitions

It’s one of those policy soundbites that just won’t die: 

“Anybody who can go down 3,000 feet in a mine can sure as hell learn to program as well… Anybody who can throw coal into a furnace can learn how to program, for God’s sake!” 

– President Joe Biden 2019

The line suggests a kind of economic alchemy—with a bit of grit and a few weeks of job training, we can transform workers from declining industries into tomorrow’s skilled labor force. But beneath this tidy promise lies a much messier, more inconvenient truth: how we acquire skills in a modern economy isn’t linear, immediate, or interchangeable. 

The economy doesn’t reward specific skills in isolation. It rewards “sequences” of skills that follow a cumulative, layered trajectory over years of education and experience. Trying to shortcut this structure is like expecting someone to write a novel without first teaching them the alphabet. It’s not a lack of motivation or potential that blocks people—it’s the missing foundation.

A recent study published in Nature Human Behavior offers a structural explanation for why retraining is hard to get right. By analyzing over 70 million job transitions and data from nearly 1,000 occupations, researchers uncovered what they call a “nested” skill structure: a hierarchy in which advanced, specialized skills are built on top of broader, foundational ones. The catch? Without a solid grasp of basic skills like reading comprehension, numeracy, and communication, advanced retraining isn’t just difficult—it’s functionally impossible. 

The Uncomfortable Truth

Think of it as a pyramid: general skills form the wide base, while more specific, high-paying, high-skill jobs sit at the peak. You don’t get to the top without passing through the bottom layers. And here’s the kicker—these dependencies are not just logical but directional. The data show that specific skills tend to “live inside” general skills in job requirements. Being a good welder is not enough; you must possess spatial reasoning, mechanical comprehension, and communication skills. These aren’t add-ons; they’re prerequisites.

Moreover, this isn’t just about retraining time; it’s about retraining sequencing. You can’t teach someone to calibrate a robotic arm if they haven’t first built foundational literacy in technical documentation, problem-solving frameworks, and numerical reasoning. The researchers use "nested dependencies" to describe this layered learning. The best-paying and most secure jobs require a chain of skills, each building on the last.

Many American workers, including the next generation of workers still in school, are starting that climb from a troublingly low rung. The retraining conversation often assumes a kind of educational neutrality: that everyone starts with the same general skill set and just needs a nudge toward a different technical role. But if large segments of the workforce have been underserved by K-12 education—and increasingly, that’s the case—then no amount of job-specific retraining can make up for the skills never built in the first place.

For example, Harvard’s class of 2027 now includes remedial math courses in its freshman curriculum. When Harvard adds catch-up math to its elite pipeline, it’s a flashing red signal that foundational skills are eroding, even among top-tier students. 

The Persistence of Skill Entrapment

The researchers also highlight something particularly troubling: what they call “skill entrapment.” When workers enter career paths that rely on unnested or low-dependency skills that don't build on general foundations or lead to more advanced roles—they tend to get stuck. These jobs are more likely to be automated, offer lower wages, and lack upward mobility. Unfortunately, this is precisely the path many displaced workers, including coal miners, end up in when retraining focuses on short-term employability rather than long-term skill development.

Worse still, the study shows this dynamic disproportionately affects already marginalized groups. Workers who, through their education, have limited access to general skills like communication and reading comprehension are more likely to acquire unnested skills and face long-term wage penalties. This is not just a problem of fairness — it’s a structural trap baked into how our economy values and organizes skills.

Politicians and think tanks love to talk about the “skills gap,” usually in the context of there being too many job openings and not enough qualified candidates. But this study reframes the issue: the real problem isn’t that workers are untrained. It’s that they’re under-foundationally trained. They lack the general, transferable skills that unlock access to the specialized ones.

If retraining is going to work, it must prioritize general education first, not as an afterthought, but as the main event. Before we teach someone how to program a robotic arm, we must ensure they can read the manual, interpret the data, and problem-solve in real-time.

And that starts in elementary school.

Final Thoughts

The idea of retraining displaced workers is noble. But the idea that we can retrain them without repairing the foundation is wishful thinking. If our public schools struggle to teach students to read and do basic math, then our retraining policies will fail unless they account for that missing base layer.

The coal miner doesn’t need a crash course in machine ops. He needs the same thing every child in this country deserves but increasingly doesn’t get: a strong foundation in the basics. Without that, no ladder of opportunity can stand—no matter how many times we promise to build it.

The idea of retraining coal miners into factory workers is a lovely metaphor—but only if we ignore how skill-building actually works. The most valuable roles in today’s economy aren’t plug-and-play. They are the product of years of educational scaffolding, much of which is eroding beneath our feet.

Source: Skill dependencies uncover nested human Capital Nature Human Behavior DOI: 10.1038/s41562-024-02093-2