Imagine a stark choice. You can save one person who is likely to live another 30 years. Or you can save several people who may each live another ten years.
Should we prioritise saving more lives – or more years of life? This kind of trade-off sits at the heart of how health systems make decisions.
Yet do people actually agree with that principle? A new international study – based on what people told us during the COVID pandemic – suggests the answer is more complicated than this simple trade-off suggests.
Across many countries, decisions about healthcare spending are guided by a concept known as the quality-adjusted life year, or Qaly. In simple terms, this approach aims to maximise the total number of years of healthy life generated by a healthcare system.
That often means prioritising treatments that deliver more life-years overall. Saving someone with more years ahead of them is typically seen as creating more value than saving someone with fewer remaining years. In practice, this can mean prioritising younger patients over older ones.
This kind of reasoning is used by Nice in the UK – and other healthchare advisory agencies, globally – to decide which medicines should be funded. But it rests on an implicit ethical assumption: that maximising total life-years is the right goal.
Our research asked a simple question: do ordinary people actually agree?
To find out, we conducted a large survey experiment with more than 14,000 people across 12 countries, including the UK, US, China, Brazil and Uganda.
Participants were asked to imagine a life-saving vaccine that could only be given to one group. They had to choose between vaccinating a 55-year-old person (with about 30 years left to live) or one or more 75-year-olds (with about ten years left each).
The scenarios were framed around COVID, but the underlying question was broader: how should we trade off saving lives versus saving life-years?
By varying the number of older people, we could estimate how many lives participants were willing to “trade” to save one younger person.
The results reveal a clear pattern – and one not entirely consistent with the Qaly-based values that underpin many healthcare funding decisions.
People don’t think in purely mathematical terms
Most people did favour saving the younger person. Around two-thirds of respondents chose to vaccinate the 55-year-old rather than a single 75-year-old.
However, when forced to make tougher trade-offs, people did not behave as if they were trying to maximise life-years. If they were, they would have been willing to sacrifice about three 75-year-olds to save one 55-year-old (since 30 years versus ten years is a 3:1 ratio). In practice, they were willing to trade fewer.
On average, across countries, people were willing to trade about two and a half older lives to save one younger life. In other words, public preferences sit somewhere between treating all lives as equal, and strictly maximising total life-years. They don’t fully align with either.
The story becomes even more interesting when we look beyond age. In some versions of the experiment, we also varied whether the hypothetical people were working. This turned out to matter a lot. When both people had the same employment status, one 55-year-old was considered roughly equivalent to just over two 75-year-olds.
Yet when the younger person was working and the older person was not, the trade-off shifted dramatically – people were willing to sacrifice more than three older lives to save the younger worker. And when the situation was reversed – the older person working and the younger not – many respondents preferred saving the older person.
This suggests that people are not just thinking about life expectancy. They are also considering broader social factors, such as contribution, perceived need or fairness.
A gap between policy and public values
These findings raise an uncomfortable question. If health systems are designed to maximise life-years, but the public values something more nuanced, is there a mismatch between policy and societal preferences?
Our results suggest there is. People do care about life expectancy – younger lives are generally prioritised. However, they also place weight on fairness, context and social roles. Their preferences are more nuanced than the strict “maximise life-years” rule embedded in many healthcare decision frameworks.
This doesn’t mean that healthcare decisions should simply follow public opinion. These are complex ethical choices, and expert judgment remains essential.
Nevertheless, ignoring public values entirely may also be problematic. Policies that feel intuitively unfair can undermine trust, which is essential for the sustainability of policies and institutions.
Rather than abandon existing approaches like Qalys, one option may be to complement them. Decision-makers could more clearly include the public’s views by using things like discussion groups, citizen panels or other methods that balance efficiency with fairness.
Another possibility is to recognise that there is no single correct answer. Different societies may reasonably draw the line in different places – and even within countries, views vary by age, politics and experience.
Our study shows that people do not see these decisions in simple mathematical terms. When faced with real trade-offs, they weigh lives, years and social context together. Ultimately, that may be a more realistic reflection of the ethical complexity at the heart of healthcare.
Laurence Roope is supported by the NIHR Oxford Biomedical Research Centre and the NIHR Oxford Health Biomedical Research Centre.
Philip Clarke receives funding from the NIHR, UKRI and the British Academy.
Fiorella Parra-Mujica does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.