The skill blueprint behind who progresses and who gets stuck

Last year Harvard Business Review ran a feature arguing that so-called ‘soft skills’ like collaboration, mathematical thinking and adaptability are the true foundation of career success. It’s a timely reminder for organisations tempted to double down on narrow technical expertise in the age of AI.

But beneath that feature sits a deeper story. The article drew on a study published in February 2025 in Nature Human Behaviour, which analysed over 70 million job transitions across nearly 1,000 occupations. That research doesn’t just confirm the importance of foundational skills but reveals an important shift in the way work and capability are organised – a shift that is reshaping mobility, wages and the future of work itself.

At its core the study finds that modern economies are becoming more ‘nested’. Advanced, specialised capabilities increasingly depend on a base of general skills. Without that base workers are locked out of the most rewarding pathways. And as the nested structure deepens, barriers to mobility are rising.

What are nested skills?

Nested skills form a hierarchy. Specialist capabilities appear only when the broader foundations are already in place. This pattern shows how work is organised and why some workers move upward more easily than others.

The researchers from Kellogg School of Management, Seoul National University and the Complexity Science Hub in Vienna mapped how skills build on each other across almost 1,000 occupations. Think of it like a skills pyramid:

• At the broad base are general skills – such as maths, oral expression, problem-solving, reasoning and English language proficiency.
• Built on top are nested skills – more specialised capabilities (like negotiation or programming) that rely on those general foundations.
• Off to the side are unnested skills – narrow, task-specific abilities (such as repairing or dynamic flexibility) that don’t depend on the general base.

The study found that career development follows this structure. Workers usually begin with roles demanding general skills, then move into more nested, specialised paths. The payoffs – wage growth, mobility, resilience against automation – accrue only to those able to progress into the nested tiers.

Careers are cumulative – early development shapes the whole path

The study tracks how workers build skills over time and the pattern is consistent across occupations. The first five job moves carry most of the weight. This is when workers acquire the general and nested capabilities the rest of their career depends on. After this period the structure becomes harder to shift.

General and nested skills rise sharply up to around age 30 then stabilise. For many women the plateau arrives earlier, which compounds disadvantage in later progression. The researchers point out that this matters because the ability to learn specialist skills depends on the strength of this early base.

General capabilities continue to grow in specialised roles but the rate slows. A negotiator may refine critical thinking across their career but they still rely on the foundation built earlier. When those foundations are thin, later specialisation often fails to take hold.

This raises important questions for HR. Graduate, apprenticeship and early-talent programmes often prioritise technical proficiency, yet the evidence shows the returns come from strengthening reasoning, communication, maths and other general skills long before technical depth is added. These capabilities accelerate learning, improve adaptability and create mobility options later in life. Without them workers frequently remain in roles with limited pathways, increasing the risk of entrapment.

The study shows that skill development is sequential and builds in layers. When foundations are weak, higher tiers rarely develop. The order matters and it is hard to change later in life.

The shrinking half-life of technical expertise

Technical know-how now becomes obsolete at astonishing speed. The ‘half-life’ of technical skills – the time it takes for a skill to lose half of its value or relevance – is now just 2.5 years in some areas.

The result is a volatile market for niche expertise. As the research authors point out, Hadoop engineers, Flash specialists and blockchain developers have all seen demand spike, then collapse. What endures is the ability to adapt: maths and reasoning to grasp new systems, communication to collaborate across teams and problem-solving to apply technology effectively.

As the study shows, workers with strong foundational skills learn new specialisations faster and pivot more easily when old skills lose relevance. In other words, these capabilities are the true hedge against obsolescence.

Winners and losers in the skill hierarchy

The nested structure produces predictable divides:

• Nested skills command premiums. Roles demanding them require more education and deliver higher wages. Workers with strong general skills are also less likely to be displaced by automation.
• Unnested skills carry penalties. Workers in these areas see limited wage growth, fewer progression routes and higher automation risk. Without access to general skills they are effectively stuck in “skill traps”.

The researchers call this skill entrapment, and it’s not just an individual problem. For organisations skill entrapment creates pockets of vulnerability: entire groups of employees whose skills are brittle, hard to redeploy and at risk of being left behind in the next disruption.

Inequality embedded in skills

Of concern to HR leaders is the fact that the research surfaces demographic disparities.

• Race and ethnicity. Black and Hispanic workers are more likely to be concentrated in roles requiring unnested skills, contributing to persistent wage penalties. Among Hispanic workers lack of English language proficiency often blocks access to nested skills, creating long-term disadvantage.
• Gender. Women’s accumulation of general and nested skills plateaus around age 30, which coincides with the typical age range for first-time mothers in the US. Men continue to grow these skills into their 40s and 50s. The effect directly contributes to the gender pay gap.
• Geography. General skills cluster in urban areas and explain a large share of the wage premium cities attract. Workers in smaller towns are less likely to access the pathways that lead into high-value nested skills.

These findings sharpen debates on inclusion and mobility. They show that equity is not just about representation in roles but about access to foundational capabilities that unlock progression.

Social skills: the glue of complex work

Social capabilities – communication, empathy, conflict resolution – are increasingly valued. They sit at the centre of the skills system. They connect many other abilities and enable workers to progress into more complex roles. Negotiation, for example, depends on oral expression and reasoning while enabling further specialisations.

This matters because modern work is woven from cross-functional teams, hybrid environments and constantly updating tools. As technical complexity rises, the glue that keeps organisations productive is human skill – the ability to connect, align and reduce friction.

For people leaders the implication is clear: social skills are not “soft”. They are structural and hold the modern skills system together.

“Specialised skills can spike and vanish this quickly, but our findings suggest that the people who ride out each wave shared the same toolkit: strong abilities to problem-solve, clear communication styles and the ability to work well with teams,” say the authors. “These core strengths help workers relearn faster, let companies redeploy talent without starting from scratch, and ultimately anchor performance when the next technology arrives.”

And as they conclude: “In a world of constant disruption, organisations should pay even closer attention to their employees’ foundational skills – because those are what make long-term adaptability possible.”