Look at the deductions on a payslip and one of them is buying you a retirement. It has the feel of saving: money set aside now, out of reach, to be handed back when you are old. But in most countries the pension the state runs does not work that way: the money is not being set aside at all. It is going straight out again, that same month, to people who are already retired, on the understanding that when your turn comes the deductions from someone younger will pay you. The pension is a promise rather than a pot, and the promise rests on an assumption so old it is rarely stated: that there will always be a crowd of working people behind you, younger and more numerous, to be taxed for your keep. That assumption was true when the system was designed. This chapter is about what happens to the promise now that it is coming untrue, and about the handful of things a country can do once it does.
A promise between the generations
The arrangement most rich countries run is called pay-as-you-go, and the name is exact. Contributions taken from today’s workers are not invested and held; they are paid out immediately as today’s pensions, and today’s workers earn a claim on the contributions of tomorrow’s. The system holds no fund with your name on it. What it holds is a chain of promises linking one working generation to the retired one in front of it and the working one behind. That design has real virtues. It could pay pensions from its very first year, without waiting decades for a fund to accumulate, and it protects the old from the swings of financial markets, because their income comes from the current wage bill rather than from the value of assets. What it cannot protect against is a change in the numbers of the people at each end of the chain. Its arithmetic is fixed to a shape: many workers, fewer retirees, drawn from the population pyramids of the mid-twentieth century, when families were large and old age was short.
The shape of a population, and why it inverts as birth rates fall and lives lengthen, is the subject of the Countries volume and its chapter on whether an aging population is an economic time bomb, and the mechanism is not retold here. What matters for the pension is a single ratio it drives: how many working-age adults stand behind each person old enough to have stopped. That number is the ground the whole promise is built on, and it is giving way.
The number to hold onto is the fall from about ten to a projected three and a half. A system built when ten workers stood behind each retiree is being asked to go on paying as the crowd thins toward three and a half, and the contributions of those three and a half have to cover a pension that ten used to share the cost of. This is not a forecast of collapse; it is a statement of arithmetic. Nothing in it says the promise cannot be kept. It says only that keeping it will cost each remaining worker far more than it did, unless something about the promise itself is changed.
The promise also grew
The thinning crowd is only half of the squeeze. The other half is that the promise being funded has quietly grown larger, because retirement lasts longer than it used to. When contributory pensions were first designed, old age was a short coda to a working life; a person reaching the pension age could expect a handful of years beyond it. Those years have multiplied. One measure of it is the number of years a person can expect to live after leaving work for good, and across the rich countries it climbed for four decades before levelling off.
Put the two figures together and the pressure on the promise is plain. The crowd paying in is thinning toward a third of its old size, and the span each pension must cover has grown by years. A contract priced for many payers and a short payout is being asked to honor few payers and a long one. Something has to give, and because the arithmetic is not a matter of opinion, the question is which of the promise’s terms absorbs the strain.
The four levers
A pay-as-you-go system has, in the end, four main levers, because the sum it pays out must come from somewhere. It can move the age at which the pension starts, so that people work longer and draw for fewer years. It can raise the contributions taken from those still working. It can lower the benefits it pays, whether openly or by letting them rise more slowly than wages or prices. Or it can enlarge the working population that pays in, which in a low-birth-rate country means immigration. The reforms of the current wave pull some combination of these four, and each is being pulled, hard, somewhere in the world right now.
Take the age lever first. Among the OECD’s members Denmark has gone furthest with it, its parliament voting in 2025 to raise the state pension age to 70 for everyone born after 1970 and tying it by earlier agreement to rising life expectancy, so that as people live longer the pension age climbs with them. The contribution lever is being pulled in Korea, which legislated in 2025 to raise its national pension contribution rate from 9 percent of wages, split evenly between workers and employers, to 13 percent by 2033, climbing half a point a year from 2026. The benefit lever is being pulled in Czechia, which legislated in 2024 to trim how new pensions are computed, phasing down between 2026 and 2035 both the share of past earnings that counts and the rate at which each year of work earns pension. And where the promise is instead being defended, the same lever becomes a running cost: the United Kingdom’s “triple lock” raises the state pension each year by the highest of prices, earnings, or two and a half percent, which lifted it by 4.1 percent in April 2025 and steadily raises the bill the young must fund. And the migration lever is explicit in Germany’s 2023 Skilled Immigration Act, which eased the path for workers from outside the European Union precisely because the working-age population is set to shrink by millions, and a pension system paid from the wage bill needs wages being earned. Each lever has a constituency it hurts, which is why none is pulled far without a fight, and why every country pulls a different mix.
Beyond the levers lies only a change of design. The money paid to retirees is either earned by workers and handed across, or set aside in advance and invested, and pay-as-you-go chose the first. Funded systems, which choose the second, escape the direct dependence on the support ratio but take on the market risk the pay-as-you-go design was meant to avoid, and a system can mix the two, funding part of the promise in advance. Nor is the switch free: moving from pay-as-you-go toward a fund means paying twice for a time, for the retirees in front and for the fund being built, a cost that lands on one generation or is spread across several by borrowing. For the promise as most countries have made it, the levers are the working toolkit, and it survives exactly to the extent that a society is willing to pull them.
The pension system is a Ponzi scheme.
Oversimplified Moderate confidence
The analogy grips because it points at something true, which is why the ruling is not that its opposite holds. A pay-as-you-go pension really does pay today’s retirees out of today’s contributions rather than from a fund saved in their name, and it really does depend on a further generation arriving to pay the current workers in their turn. Anyone who pictures a personal pot quietly growing with their own money is mistaken about the mechanism; on the flow of the money itself, the claim is closer to the truth than the comfortable picture it replaces. What the analogy then imports, and what does not fit, is fraud and inevitable collapse. A Ponzi scheme is a deception: it pretends to generate returns from investment while secretly paying old investors with new investors’ money, and it must collapse when recruitment slows, because there was never any real activity underneath. A public pension’s design is no secret; pay-as-you-go is legislated and openly described. Beneath it sits genuine ongoing activity, the labor of each working generation, and behind it sits the state’s power to tax and to adjust the terms. That is why it need not collapse when the numbers move against it: it has the four levers, the retirement age, contributions, benefits, and the size of the working population, and it can pull them, which a fraud by its nature cannot. The strain the thinning support ratio puts on the promise is real, and a system that refused to pull any lever could indeed break. But a design that pays current claims from current activity, discloses exactly what it is doing, and can be adjusted is not the fraud the word names. The claim takes the real pay-as-you-go structure and stretches it into an accusation of deception and doom that the structure does not carry. It is oversimplified rather than backwards: what it says about the flow of the money is true, and the deceit and the doom it adds are not.
Sources
- The mechanism: pay-as-you-go pensions fund current benefits from current contributions and hold no personal fund, so they depend on the ratio of workers to retirees. The support ratio for the world fell from about 9.99 working-age adults (aged 20–64) per person 65 or over in 1950 to a projected 3.47 in 2050 on the medium variant: UN World Population Prospects 2024 revision, computed from the population-by-age file. The demographic mechanism itself is treated in the Countries volume, on whether an aging population is a time bomb.
- The lengthening payout: expected years of life after leaving work, OECD average, rose for men from about 12 in 1970 to about 19 by 2011 and then levelled to about 18.6 by 2024 (OECD, Pensions at a Glance 2025, expected life years after labour market exit). It is a derived measure, life expectancy at the average effective exit age, and is best read for its trend.
- The levers being pulled now: Denmark legislated a state pension age of 70 for those born after 1970, tied to life expectancy (2025); Korea legislated in 2025 to raise its pension contribution rate from 9 to 13 percent of wages by 2033; Czechia legislated in 2024 to phase down how new pensions are computed between 2026 and 2035, while the United Kingdom’s triple lock, which raised the state pension by 4.1 percent in April 2025, holds the same lever open; and Germany’s 2023 Skilled Immigration Act eased non-EU labor entry against a shrinking working-age population. Each is a real, dated instance of one lever.
- Confidence is moderate under the rubric, which scores the weaker of evidence directness and construct match. Evidence directness is strong: the support ratio is measured history joined to a standard projection, the years-in-retirement series is measured, and the reforms are matters of legislation. The binding, weaker leg is construct match. “Ponzi scheme” is a loaded analogy carrying features, deliberate fraud and necessary collapse, that a disclosed, taxation-backed, adjustable public system does not share, even as it does share the pay-as-you-go structure the analogy fastens on. The direction is clear, which holds the ruling firm and the confidence off low; the analogy’s partial fit is what keeps it off high.
Where the volume has arrived
This is the last chapter of the book, and it closes on the same question the volume opened with, now asked about the end of a working life rather than its worth. The book began by asking what a job is worth and found the answer in bargaining position rather than moral desert; it followed the paycheck as it lost the race with a growing economy, asked why governments keep a margin of unemployment on purpose, walked through the charged fights over the minimum wage, the pay gap, immigration, and executive pay, drew the boundary around the unpaid work that never enters the accounts, and then watched work itself shrink, in the hours it takes, in the tasks machines take over, and in the meaning it leaves behind. Retirement is where the working life is meant to end well, and it too turns out to be a settlement rather than a given: a promise between the generations, priced on a demography that has since inverted, kept alive only by choices a society makes about who works how long, who pays how much, and who is let in to help carry the load. Running through the whole volume is one finding. What a job pays, whether the raise arrives, who does the work that goes uncounted, and whether the pension holds are the outcomes of arrangements that were built, and can be rebuilt, rather than facts of nature. Work is something a society decides the shape of, and the shape it has is one of the things most worth arguing well.