More or Less

Tim Harford investigates some of the numbers in the news. This week:

Headlines have claimed that “healthy life expectancy” in the UK has fallen by two years. What does this actually mean? (00:32)

A new government report estimates that HS2 will cost almost double its original estimate. We ask where the money’s gone. (10:26)

Chancellor Rachel Reeves has reduced VAT on theme parks, aquariums and other summer fun. But will these savings get passed on to the consumer? (21:07)

And Tim gives a much-anticipated update on his recent marathon. (09:10)

Contributors:

Credits:

What does it mean if you say that something is an epidemic? In the case of a virus, it usually means that it is spreading rapidly and that more and more people are getting infected. When a disease is not on the rise but is there in a population at a reasonably steady level, we tend to say that the disease is endemic.

But what if the thing you are talking about is not a virus, but a feeling? In 2023, the US surgeon general launched a report called Our Epidemic of Loneliness and Isolation, warning of the health harms of being lonely and socially isolated.

The idea that there is an epidemic of loneliness did not start there - the term was already in use in the US in the 2010s. And it is a phrase that is still going strong, popping up in news stories on a regular basis.

After that warning from the US surgeon general, the World Health Organization launched the Commission on Social Connection, with their director general warning that “more and more people are finding themselves isolated and lonely”

But is it true that loneliness rates are increasing? Is it right to say we’re in the midst of an epidemic of loneliness?

We speak to Prof Melody Ding, an epidemiologist and population behavioural scientist at the University of Sydney.

If you’ve seen a number in the news you think we should take a look at, email [email protected]

This programme has been edited to correct a minor technical production error on 27/05/2026

Presenter: Tim Harford

Tim Harford investigates some of the numbers in the news. On the programme:

Last week, Annunziata Rees-Mogg took to X to post a claim about the proportion of sex offences in Dorset that are committed by asylum seekers, writing that “asylum seekers make up 0.8% of Dorset’s population and 44% of alleged sex offenses. So unbelievable I had to check.” We checked too, and the number isn’t right.

In the last series of More or Less we suggested that nuclear power plant Hinkley C was spending so much on protecting the fish population that it would cost something like £250,000 per fish saved. We’ve had to take a look at that one too.

Last year, we looked at a report by the Bible Society based on polling from YouGov. The Quiet Revival suggested that churchgoing was on the rise in the UK, with young men leading the trend. YouGov now have an update on that survey.

How many caterpillars does a blue tit chick eat before it leaves the nest? In a recent nature documentary, Sir David Attenborough said the right number was 20,000. We’re not so sure.

If you’ve seen a number in the news you think we should take a look at, email the more or Less team: [email protected]

CONTRIBUTORS:

Madeleine Sumption, Director of the Migration Observatory at Oxford University

CREDITS

Presenter: Tim Harford

It is said that AI could soon be coming for the jobs of artists, lawyers, and software engineers. But it might now also be threatening a role at the height of academia – are pure mathematicians safe?

According to the World Health organisation, smoking kills some 7 million people every year. It is one of the world’s leading causes of preventable death.

But the World Health organisation is also concerned about vaping. Last year they said 100 million people around the world are now using e-cigarettes, including millions of children, and warned that they were fuelling a new wave of nicotine addiction.

But how do the health risks of these two means of getting nicotine into your bloodstream compare?

According to a recent headline in the Daily Mail, they’re basically the same. Here’s the headline:

“Vaping is linked to lung and mouth cancer in major study, as experts warn: 'It is NOT safer than smoking’”

But is vaping really just as bad for you as smoking?

CONTRIBUTOR:

Professor Lion Shahab, Co-Director of the UCL Tobacco and Alcohol Research Group

CREDITS:

Presenter: Charlotte McDonald

If you spend much time on social media, and we don’t necessarily recommend it, then you’ve probably come across a strange fascination with water consumption.

Mainly, this is people telling you that using AI is terrible for the planet because of how much water it uses. We’ve already made a couple of programmes about the numbers in those arguments and, long story short, they probably aren’t saying what you think they’re saying.

But on platforms like X, BlueSky, and TikTok, an opportunity to keep an argument going is rarely missed.

And one of the numbers that’s been enlisted in that glorious cause concerns the water that’s used for a seemingly unrelated past-time - eating beef. Here’s an example from a user on X:

“A kilogram of beef requires over 15,000 litres of water to produce,” they wrote. “A vegan who uses ChatGPT every day is living a more sustainable lifestyle than someone who regularly eats beef while boycotting AI.”

Ignoring the AI part, is that true? Does it actually take 15,000 litres of water to produce a kilogram of beef?

It turns out that the number isn’t wrong, but it probably isn’t saying what you think it’s saying.

If you’ve seen a number you think we should take a look at, email the More or Less team: [email protected]

CONTRIBUTORS:

Vaccine policy in the US is something of an ideological battleground.

At the same time, last year saw the worst measles outbreak in the US in decades. There were more than 2000 cases last year, and three people died. There have been more than 1500 cases so far in 2026.

There’s a lot going on, so it’s possible the public’s views on vaccination are shifting.

A new poll published by online news site Politico added a big claim into the mix. According to the headline “more Americans doubt vaccine safety than trust it”.

But is that what the survey actually found?

Dr David Higgins, a paediatrician and public health assistant professor who writes a Substack called Community Immunity, explains why he believes the headline is misleading.

If you've seen a number in the news you think we should take a look at, email [email protected]

Presenter: Charlotte McDonald

US president Donald Trump is no fan of wind turbines, or windmills as he calls them.

Not only does he think they ruin the view from a golf course he owns in Scotland, but they are also deadly to birds.

“If you love birds, you’d never want to walk under a windmill,” he said in 2019.

“It’s a very sad, sad sight. It’s like a cemetery. We put a little statue for the poor birds.”

Earlier this year he posted on Truth Social saying that wind turbines were killing “millions” of birds.

But is that true? We speak to Dr Hannah Ritchie, Deputy Editor at Our World in Data and senior researcher at the University of Oxford, who has dug into the numbers on bird mortality and wind turbines.

Credits:

Presenter: Charlotte McDonald

Sometimes it is obvious to everyone when an idea is harmful, or a piece of advice is damaging. But not always. Occasionally bad ideas and terrible advice end up being accepted in society and supported by people in authority.

In such circumstances, one of the most powerful tools for changing people's minds is evidence – scientific studies that show beyond doubt that the bad idea is, indeed, a bad idea.

That's the subject of a new book by Helen Pearson, titled Beyond Belief: How Evidence Shows What Really Works.

An editor at the scientific journal Nature in her day job, the book chronicles those determined individuals who shake up the status quo by gathering just the right kind of evidence.

One story in that book stood out to us on More or Less as it shows just what happens when you don't have the evidence you need to challenge a dangerous way of doing things.

It's the story of a piece of advice from childcare expert Dr Benjamin Spock.

In a 1958 revision of his bestselling parenting guide Baby and Childcare he made a small change to his advice on sleeping position – advising parents to put their babies to sleep on their front.

It eventually became clear that this sleeping position was associated with a significant increase in the risk of sudden infant death, or cot death.

CREDITS:

Presenter: Charlotte McDonald

When you’re listening to the news, you will often hear words that are meant to communicate the probability of something happening.

But when you hear these terms, do you really know what kind of probabilities they’re trying to convey? Do you know how likely “likely” is? Or what probability “probable” is meant to get across?

In some cases, it seems you probably don't.

Professor Adam Kucharski, author of Proof, the Uncertain Science of Certainty, designed a quiz to work out the actual probabilities of the language we use to convey risks.

The data he got back shows how sometimes these words mean very different things to different people.

If you want to try the quiz for yourself, head over to https://probability.kucharski.io/

Email the More or Less team: [email protected]

Presenter: Charlotte McDonald