The middle class is the social class most rapidly shrinking across modern economies. Across OECD countries, the share of people living in middle-income households dropped from 64% to 61% between the mid-1980s and mid-2010s, and each new generation enters the middle class at lower rates than the one before it. That three-percentage-point shift sounds modest until you consider the tens of millions of people it represents, and what they lost in economic influence along the way. The forces behind this squeeze are neither mysterious nor confined to one country, but they interact in ways that make the trend stubbornly hard to reverse.
How the Middle Class Is Defined and Why It Matters
Economists typically define middle-income households as those earning between 75% and 200% of the national median income. By this measure, the middle class once represented the economic center of gravity in wealthy nations. Three decades ago, the combined income of all middle-income households was roughly four times the combined income of upper-income households. Today that ratio has fallen to less than three.
The generational dimension is striking. About 70% of baby boomers belonged to the middle class in their twenties. Among millennials at the same age, that figure dropped to 60%.1OECD Publishing. Under Pressure: The Squeezed Middle Class People are not simply cycling through the middle class on their way up. Many are falling out of it, and fewer are entering it in the first place.
Job Polarization and the Hollowing Out of Middle-Skill Work
The single biggest structural force behind the shrinking middle class is job polarization: labor markets across wealthy countries have been gaining jobs at the top and the bottom of the skill spectrum while shedding jobs in the middle. Middle-skill occupations like bookkeeping, assembly-line manufacturing, clerical administration, and routine technical work have contracted as a share of total employment in nearly every OECD country over recent decades.2OECD Publishing. Job polarisation and the middle class: New evidence on the changing relationship between skill levels and household income levels from 18 OECD countries
Technology is a primary driver. As the cost of information technology has fallen, industries that depend heavily on IT have seen middle-wage jobs shrink while high-wage employment grows. A study of ten Western European countries found that sectors with greater IT dependence lost a larger share of middle-wage positions compared to sectors that relied less on computing.3Oxford Bulletin of Economics and Statistics. Automation and Job Polarization: On the Decline of Middling Occupations in Europe The pattern is not one of pure job destruction. It is a reshuffling: high-skill analytical roles and low-skill service roles both expand while the routine middle gets compressed.
This matters for wages as much as for job counts. The occupations that disappear tend to be the ones that once paid enough to sustain a middle-class lifestyle without requiring a graduate degree. The new low-skill service jobs that replace them, in areas like food preparation, personal care, and warehouse fulfillment, rarely offer comparable pay or benefits.
Globalization Pushed Workers Out of Middle-Wage Industries
Technology did not act alone. Trade liberalization and offshoring put direct downward pressure on wages in sectors where middle-class jobs were concentrated, especially manufacturing. Research on American workers found that both offshoring to low-wage countries and rising imports were associated with significant wage declines. Workers displaced from high-wage manufacturing jobs were reallocated into other sectors and occupations, and those who switched experienced large pay cuts.4National Bureau of Economic Research. Why are American Workers getting Poorer? China, Trade and Offshoring
When viewed globally, the picture is more complicated. Growth in global incomes from the 1980s onward has an uneven “elephant curve” shape: incomes grew rapidly around the global median, driven by rising living standards in countries like China and India, grew modestly for those above the median (the lower-middle and middle classes in wealthy nations), and then grew explosively again at the very top.5AEA Papers and Proceedings. The Elephant Curve of Global Inequality and Growth In other words, globalization pulled hundreds of millions of people in developing countries into a new global middle class while simultaneously squeezing the middle class in rich countries. The group that stagnated was the one that had the most to lose: factory workers, office clerks, and mid-tier professionals in North America, Western Europe, and parts of East Asia.
Rising Costs Eat Into What the Middle Earns
Even for households that still qualify as middle-income on paper, the lived experience of middle-class life has eroded. The cost of the essentials that define a middle-class standard, including housing, healthcare, childcare, and education, has risen faster than median incomes in most wealthy countries for decades.
Research on middle-income families shows that both rural and urban households have shifted their spending toward essentials, with non-essential categories like education, recreation, and clothing seeing cuts.6International Journal For Multidisciplinary Research. The Effect of Rising Cost of Living on the Expenditure Behaviour of Middle-Income Families That kind of spending compression is what economic vulnerability looks like in practice. You are technically middle-income but spending like someone who cannot afford a surprise expense, because increasingly you cannot.
Housing deserves special mention. In major cities, property prices have risen so far beyond median wages that homeownership, once the signature marker of middle-class stability, has become unreachable for many. In London, for instance, researchers have found that shifts in housing access, including an increasingly competitive rental market alongside inflated property prices, are disrupting the way the middle class reproduces itself across generations. Expectations about housing futures, once a source of confidence, have become a source of anxiety.7PubMed. Making the middle classes on shifting ground? Residential status, performativity and middle-class subjectivities in contemporary London When a household earning above-median income cannot afford to buy a home in the city where it works, the economic definition of “middle class” and the cultural reality of it have diverged.
The Decline of Unions Weakened the Middle Class’s Floor
Institutional shifts have reinforced the market forces squeezing the middle. In the United States, private-sector union membership dropped from 34% to 8% for men and from 16% to 6% for women between 1973 and 2007. Over the same period, hourly wage inequality grew by more than 40%. Research suggests the decline of organized labor explains somewhere between a fifth and a third of that growth in inequality, an effect on the same scale as the growing gap in wages between workers with and without college degrees.8American Sociological Review. Unions, Norms, and the Rise in U.S. Wage Inequality
Unions did not just raise wages for their own members. They also helped set norms of pay equity that restrained wage dispersion even among non-union workers in heavily unionized industries and regions. As those norms weakened, the floor beneath middle-class wages dropped. Union workers are disproportionately found in the middle-income group or above, and the union wage premium pushed some workers into middle-income status who would otherwise have fallen short.9NBER. How Does Declining Unionism Affect the American Middle Class and Intergenerational Mobility? The relationship between union decline and middle-class shrinkage is not proven to be purely causal, but it is strong and consistent enough that most economists treat de-unionization as a meaningful contributor.
Fewer People Earn More Than Their Parents
The clearest sign that the middle class is disappearing may be generational. “Absolute mobility,” the chance that a child grows up to earn more than their parents did at the same age, has been falling across wealthy nations for decades.10American Economic Journal: Applied Economics. The Long-Run Evolution of Absolute Intergenerational Mobility In the United States, about 90% of children born in 1940 went on to earn more than their parents. For children born in the 1980s, that figure had dropped to roughly 50%.11PubMed. The fading American dream: Trends in absolute income mobility since 1940
A common assumption is that faster GDP growth alone would fix this. But the same research found that returning to higher growth rates would not restore mobility to the levels seen in the mid-20th century. What mattered more was how growth was distributed. Spreading current GDP growth across income groups the way it was shared for children born in 1940 would reverse more than 70% of the decline in mobility.12PubMed. The fading American dream: Trends in absolute income mobility since 1940 Growth happened, in other words, but it stopped reaching the middle.
This matters globally, not just in the United States. Declining labor shares of income, meaning the portion of total economic output going to workers rather than capital owners, have been documented across both high-income and developing countries.13Review of Income and Wealth. Measuring the Labor Income Share of Developing Countries: Lessons From Social Accounting Matrices When a shrinking slice of the economy goes to wages, the middle class contracts almost by definition.
The Gender Dimension of Polarization
Job polarization has not affected men and women equally. Research covering the 1980–2017 period in the United States found that employment polarization was largely generated by women. As the gap in wages between high-skill and low-skill work widened, more high-skilled women entered the labor force, worked fewer hours at home, and purchased more market substitutes for home production, things like childcare, cleaning, and food preparation. That dynamic fueled growth in low-wage service employment at the bottom of the skill distribution.14CrossRef API. THE ROLE OF GENDER IN EMPLOYMENT POLARIZATION
The result is a layered story. High-skilled women gained from polarization; low-skilled women filled the new service roles; and middle-skilled workers of both genders watched their job categories thin out. Any policy response that ignores how these dynamics vary by gender will only address part of the picture.
Geographic Concentration and the “Dual City”
The decline of the middle class is also playing out spatially. In major cities, neighborhoods that were once economically mixed have been sorting into wealthier and poorer areas, with the middle-class neighborhoods in between shrinking. Scholars have described this process as the emergence of “dual cities” where the rich and poor become further apart both socially and geographically while the middle class hollows out.15Elsevier (Cities). Neighbourhood change and spatial polarization: The roles of increasing inequality and divergent urban development
This is self-reinforcing. When middle-class families are priced out of urban cores, they lose access to the job markets, schools, and social networks that help people stay in or climb into the middle class. Meanwhile, prosperous neighborhoods become enclaves where property wealth insulates families from economic shocks. The physical landscape of a city starts to mirror the labor market: lots at the top, lots at the bottom, and a shrinking middle.
Political Fallout
A shrinking middle class does not just change economic statistics. It changes elections. Research has found that the workers most directly harmed by job polarization, blue-collar and white-collar routine workers in the lower middle class, are a large and electorally active group. Unlike the very poor, they have the resources and habits to participate in politics. When their labor market prospects darken, they generate demand for social, cultural, and economic protectionism.16Research & Politics. Shrinking and shouting: the political revolt of the declining middle in times of employment polarization
Socially conservative and right-wing populist parties have been particularly effective at mobilizing these voters by acknowledging their economic anxieties and framing them in cultural terms. The electoral upheavals of the past decade in the United States, the United Kingdom, France, and elsewhere are hard to explain without understanding this dynamic. A lower middle class that no longer feels protected from economic modernization becomes a powerful and volatile political force.
The Psychological Toll of Downward Mobility
Beyond politics and economics, losing middle-class status or fearing you will carries a measurable psychological cost. Experimental and observational research has found that beliefs about downward mobility consistently increase status anxiety, which in turn reduces life satisfaction and broader well-being. The effects of downward mobility beliefs are stronger and more consistent than the effects of upward mobility beliefs, meaning the anxiety of falling hits harder than the hope of rising.17PubMed. Prospects of Downward Mobility Cause Status Anxiety and Life Dissatisfaction
This creates a feedback loop. Workers in shrinking middle-skill occupations see their prospects narrowing, experience greater anxiety, and may disengage from the job search process or make risk-averse decisions that limit their economic recovery. The OECD has noted that mid-career workers displaced by structural change often face obsolete skills and no recent job-search experience, but also bring histories of stable employment and strong motivation. Early counseling on realistic re-employment strategies can help, yet many countries underinvest in this kind of targeted support.18OECD iLibrary. Under Pressure: The Squeezed Middle Class
Could AI Rebuild Middle-Class Jobs Instead of Destroying Them?
The usual framing treats technology as the enemy of the middle class. Automation displaced routine jobs, so artificial intelligence will presumably displace more. But some researchers have argued the relationship does not have to be adversarial. An NBER working paper makes the case that AI, if deployed thoughtfully, could help restore the middle-skill, middle-class core of the labor market that automation and globalization hollowed out.19NBER. Applying AI to Rebuild Middle Class Jobs
The idea is that AI can augment rather than replace workers by handling the routine components of a task while leaving the judgment, interpersonal, and adaptive components to humans. A medical coder who once spent hours on repetitive data entry might instead use AI tools to handle the routine portion and spend more time on complex cases. A manufacturing technician could use AI-assisted diagnostics to manage a wider range of equipment. If this plays out, jobs that were hollowed out by the first wave of automation could be rebuilt in a new form, with AI handling what computers do well and humans contributing the flexibility that machines still lack.
Whether this optimistic scenario materializes depends almost entirely on how firms choose to deploy AI and how policy steers those choices. The same technology can be used to eliminate a position or to make that position more productive and valuable. History suggests that without deliberate policy intervention, the labor-saving path tends to win out. The previous wave of IT-driven automation overwhelmingly displaced middle-skill work rather than augmenting it, and there is no technical reason AI could not follow the same pattern. The question is whether governments and employers will make a different choice this time around.