Does the average American have fewer than three friends?

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Suffs!

The new musical has made Tony award-winning history on Broadway.

We demand to be home!

Winner, best score!

We demand to be seen!

Winner, best book!

We demand to be quality!

It's a theatrical masterpiece that's thrilling, inspiring, dazzlingly entertaining, and unquestionably the most emotionally stirring musical this season.

Suffs!

Playing the Orpheum Theater, October 22nd through November 9th.

Tickets at BroadwaySF.com

BBC Sounds, Music, Radio, Podcasts.

Hello, and welcome to a brand new series of More or Less, the show that sprinkles a refreshing shower of statistical insight over the parched lawns of misinformation.

This week, Mark Zuckerberg of Facebook says that most people don't have many friends.

We'll leave that claim there for now.

Two enthusiastic doctors reckon that 90% of cases of Alzheimer's disease can be prevented, which is huge, if it's true.

We speak to someone who's almost the new Pope about the statistical evidence for the existence of God.

But first, claims about what immigrants contribute to the exchequer.

Loyal listener Barney got in touch to ask about a claim he heard London Mayor Sadiq Khan make on LBC.

A skilled migrant's family will contribute to the British economy £12,000 a year.

That's when you, even when you take away public services they use, a British skilled worker's family takes from the economy £4,400 when you include public services they use.

Barney wondered if we could check these numbers and explain them.

Sure thing, Barney.

The figures come from the Migration Advisory Committee's annual report.

As it happens, Madeline Sumption, friend of the programme and director of Oxford University's Migration Observatory, also happens to be the Deputy Chair of the Migration Advisory Committee.

Welcome back to more or less, Madeline.

So Sadiq Khan, the Mayor of London, told LBC

that a skilled migrant's family will contribute £12,000 a year and a British skilled workers' family takes from the economy £4,400.

I presume he's talking about tax rather than actually taking from the economy, but making allowances for that.

Is he right?

So, Sadiq Khan is using real figures here, but he's describing them incorrectly.

Where he's gone wrong is saying that the comparison is between a skilled worker and a visa and a skilled British worker.

Actually, the comparison is with the average UK adult, and that includes people who are not working, people who are retired, people who are working but earning much less than you would be allowed to earn on a skilled worker visa.

In general,

there are lots of things that affect your fiscal impact, your impact on public finances, but someone who's doing the same kind of skilled job, so for example, a computer programmer earning £50,000 a year, they're going to have a positive fiscal impact, and that's going to be true whether or not they're a migrant or a British person.

Yes.

Do we know what the right figures would be for the description that he has used?

I think what he's trying to say is that a skilled migrant's family taken as a whole contributes more to the treasury net than a skilled worker's family if that skilled worker is a British citizen.

Do we know if that's right?

Yeah, so we've got two different comparisons here.

We've got the comparison between a skilled worker, say someone like a computer programmer or a graphic designer, themselves on their own, and then with their family members.

And in both cases, if you're talking about a migrant or a British person, the skilled worker, if they're earning an amount like £50,000, for example, they're going to have a significant positive impact on public finances, more or less regardless of their visa status or where they come from.

Their family members are more likely to have a negative fiscal impact.

And this, I think, is another

area where what he said wasn't quite right, which is that he says that the family members also have a positive impact.

That's not true.

The numbers that he's using suggest that there was a positive impact from the skilled migrant worker themselves of around £16,000,

but that the household as a whole had a positive impact of around £12,000.

So you've got just over £4,000,

which is the negative impact of the family members.

So the family members of migrants have a negative fisc impact.

That's also going to be true on average of the family members of British people.

Remember that some of these are children and so by definition children have a fiscal fact that...

Children don't pay tax but you have to pay for their doctor's appointments and you have to pay for them to go to school and all of those things and the same for pensioners.

So it doesn't mean there's anything wrong with them as people.

I guess we shouldn't be surprised that people of working age are more likely to be making a contribution.

That's right.

And if you look specifically at this group of people on skilled worker visas, that is the point in their life cycle when they're most likely to be making a positive contribution.

They've come to the UK, they've given a visa that requires them to be in work,

and they obviously have many years to go until retirement.

They tend to be quite young, and so the spending on the NHS is much lower for younger people than older people.

So, all of these things mean that it's not particularly surprising that you're going to get quite a significant positive fiscal impact when you do that particular comparison.

And why would the average British household

have a negative net fiscal impact?

Minus £4,400, so it's

about £80 £80 a week.

Where's that money going?

So the UK is running a budget deficit at the moment, and that means that the average person is having a negative net fiscal impact.

So that money effectively is going to all of the things that we spend money on as a country, health and care, other public services, state pensions, welfare and debt interest would be the main ones.

When we asked the Mayor about the claim, his office told us the fundamental point he was getting at was that skilled migrant workers make a positive net contribution to the UK and that the Migration Advisory Committee report supports this claim.

How much confidence should we have in any of these numbers?

Presumably they're all estimates.

Yes, I think at a broad brush level it is clear that skilled worker visa holders are going to have a pretty significant positive fiscal impact because they are earning a fair amount of money.

I think nailing down precisely what that impact is is much harder.

All of these fiscal models have to make quite a lot of heroic assumptions to work out how to attribute different bits of the UK's tax and spending to different people.

So, for example, you have to decide how to deal with defence spending.

Is that something that is attributed to migrants or not?

What about debt interest on spending that was incurred before they arrived in the country?

There are also lots of issues around the data.

We don't know precisely how much migrants earn, for example.

The figures in this report are taken from the visa system, but that's really a minimum of what they are required to earn under the immigration system, and many of them will be earning more.

So, I think the bottom line is that you shouldn't get too bogged down in differences of one or two thousand

here or there.

The important thing is the big picture.

Ultimately, this just comes down to how much people earn, and if you have a visa programme that lets in high-earning people, it's going to have a positive fiscal impact.

The Office for National Statistics recently announced a massive fall in net migration.

The net number of additional migrants coming into the UK almost halved between 2023 and 2024.

Although the new number, 431,000, is still quite large by historical standards.

Does that fall in net inward migration mean the government's going to have less money to play with?

There's been a lot of commentary about the decrease in net migration suggesting that this is automatically a very bad thing for public finances.

I would be a little bit more cautious because what really matters, as we've been discussing, is who is coming to the UK and not how many and particularly what the people are earning when they get here.

The decreases that we have seen were largely driven by the family members of international students and by care workers and their family members.

And those are groups that are sort of in the middle of the range in terms of their likely fiscal impact.

And so overall, I actually wouldn't necessarily expect this decline that we've seen over the last couple of years in net migration to have a particularly dramatic impact on public finances.

Thanks to Madeleine Sumption from the Migration Observatory.

You're listening to more or less.

Loyal listener Peter wrote into more or less at bbc.co.uk querying a stat he heard in the wild.

Well, on the BBC anyway.

The BBC in turn was quoting the boss of Meta, Mark Zuckerberg, which owns Facebook, WhatsApp, and Instagram.

Zuckerberg was chatting with podcaster Dwakesh Patel.

Mark Zuckerberg was talking about using AI to help with loneliness.

He said that the average US citizen only has three friends.

There's a stat that I always think is crazy.

The average American, I think, has, I think it's fewer than three friends.

Three people they'd consider friends.

And the average person has demand for meaningfully more.

I think it's like 15 friends.

Now, that got me thinking, could this be correct?

Where did the number come from?

And what would the equivalent number be in the UK?

Hmm.

Well, to be honest, I haven't sat and counted my friends since I was about six.

And no, it wasn't no friends.

Back on you with no returns, I had loads of friends, actually.

Then again, I'm not your average man.

I found someone more average to look into it.

R counts all of her work colleagues as friends to boost her count to three, correspondent, Lizzie McNeil.

Hello, Lizzie.

Hi, friend.

Yeah,

so to the quote.

Right.

Yeah.

So the average person in the US has fewer than three friends.

This seems to come from a survey by Pew Research, and they were looking into family and relationship structure in the US back in 2023.

So that's a well-known source.

What was the size of the survey?

5,057 people.

And did the majority of these 5,057 people have fewer than three friends?

Not quite.

What they were asking about were close friends and according to their survey 50%

had over three close friends and 47% had three or under and the rest preferred not to answer.

So 50% had more than three

but Zuckerberg said 50% had less than three.

Yes, and actually quite a lot of people had exactly three.

So only about 30% of people had less than three.

So that's quite a big difference.

And as you say, these are close friends, not just any friends.

So why did Zuckerberg get it so wrong?

You'd have to ask him that, which we did, but got no response.

So it's not really a surprise he's not making friends.

No.

Now, tell me what we mean by a friend or a close friend.

It seems a bit subjective.

It is.

Pew Research says they left it up to the participants to define what they thought of as a close friend.

I asked around the more or less team, and different people had different views of how they'd define a close friend.

But there is a survey in the UK that asked people about friends versus close friends.

Uh-huh.

Yeah, so unsurprisingly, people have way fewer close friends than friend friends.

41% said they had two to three close friends, which is similar to the US numbers that Zuckerberg was citing.

But looking beyond close friends to friends in general, over 80% of people said they had more than three friends.

So Zuckerberg should just have said just under half of people have three close friends, but most people have more.

The picture's just not as bleak as he presented it.

Yeah, but research does suggest that you start to shed friends as you age.

What?

Uh huh.

So no one told you life was going to be this way.

Terrible.

That was terrible.

Zero rehearsal.

Anyway, there have been papers that state that the number of friends someone has does start to decline after the age of 25,

and of the respondents in the YouGov survey that had no close friends, a quarter said it's because they slowly fell out of touch.

Friendship isn't necessarily going to become some dystopian AI fever dream.

Life is busy.

Not having tons of close friends is fine.

Keep telling yourself that.

Zuckerberg also said that people would like to have 15 friends as an ideal.

Where did he get that number from?

Not the surveys.

He seems to be referencing research by Robin Dunbar, specifically the Dunbar number.

Robin Dunbar is an anthropologist who theorised that the amount of social relationships humans can cope with at any one time is 150.

And that idea originally came from comparing the size of chimp and monkey brains and the size of their social groups and extrapolating to humans.

So the bigger the brain is in relation to the body, the more relationships you can sustain.

Yeah, that's the idea, yeah.

So Dunbar then looked at historical evidence for human group sizes and how big they could get before they collapse.

According to his and others' research, 150 cropped up again and again for the size a group can get before it splits apart.

But 150 is way more than we've been discussing so far.

Yes, this comes back to the distinction between close friends and looser social relationships.

Dunbar reckons that humans typically know about 150 people socially, of whom 50 are friends or acquaintances, 15 are good friends, and 5 is the inner circle of your closest friends and family members.

Sounds exhausting.

Obviously these numbers will differ from person to person, but Dunbar's theory is that it's hard to sustain more than 15 really good friendships.

People just don't have the time or the capacity to maintain more than that.

It's like you're always stuck in second gear.

Yeah, Byton.

That was my very good friend, Lizzie McNeil.

Sucks!

The new musical has made Tony award-winning history on Broadway.

We the man to be honest!

Winner, best score.

We demand to be seen.

Winner, best book.

It's a theatrical masterpiece that's thrilling, inspiring, dazzlingly entertaining, and unquestionably the most emotionally stirring musical this season.

Suffs, playing the Orpheum Theater, October 22nd through November 9th.

Tickets at BroadwaySF.com.

Listener Paul wrote into more or less at bbc.co.uk.

Dear Tim and the Moreless team, I've recently been told about the Zoe app and a claim on it that 90% of Alzheimer cases are preventable.

This is to do with a scheme called Neuro that focuses on lifestyle changes that, if all adhered to, they claim, could stop the vast majority of cases ever happening.

Is this something that could realistically be achieved in the real world?

Or is it just a scientific theory that could never really happen in practice?

Thank you, Paul.

Many of you listening will know people with dementia caused by Alzheimer's disease.

I know people on our team do.

It's a progressive disease that causes a decline in cognitive function which can cause memory loss, confusion and other mental problems.

So preventing 90% of cases would indeed be huge.

But is it true?

Well, the claim was made on the Zoe podcast by doctors Aisha and Dean Sherzai.

Handily, they have a book and a health plan you can subscribe to to ensure you're one of the 90% of cases that are prevented.

I spoke to Rob Howard, professor of old-age psychiatry at University College London, to try to get to the bottom of all this.

Do you have any idea where they got this figure of 90%?

And what do you make of it?

So, I mean, to be polite, that's not a figure that's supported by research.

Okay.

Tell me more.

Probably about 1% of people with Alzheimer's disease will have a genetic condition, a familial dementia caused by a mutation in a single gene,

where if you carry that gene, you will 100% develop Alzheimer's disease dementia, often in your 50s.

And the families who carry these genes, of course, they know about it.

But that's a very rare cause of dementia causing about 1% of cases.

So we know there are genes that

can confer risk for Alzheimer's disease, but we also know there are lots of other factors.

I mean we know that there are lots of different routes to dementia and that even a single cause of dementia, Alzheimer's disease, seems to have many factors that can play into etiology.

If you're one of the unlucky 1% with that specific heritable gene, no amount of books or lifestyle plans can help you.

As for the other cases, well, developing Alzheimer's is often due to a long series of unfortunate events, environmental factors or risks combining with potential genetic susceptibility, causing a certain type of protein to build up in the brain, damaging cells and functionality.

I was part of the Lancet Commission on Dementia, which looked at all the literature.

looking at the various risk factors that have been described and the attributable fraction of risk that you can ascribe to each of those risk factors.

And we came up with 14 risk factors.

Do you want me to list them?

It's quite a long list, Tim.

Always.

Early life risk factor is receiving less education.

That's a risk factor for later developing dementia.

In midlife the risk factors are hearing loss, high cholesterol, being depressed, having a traumatic brain injury, being physically inactive, smoking, having diabetes, having high blood pressure that isn't treated, having obesity and excessive alcohol consumption.

Those are all important midlife risk factors.

And in late life, being socially isolated living in areas with high levels of air pollution and having untreated vision loss those are all significant risk factors for developing dementia so when we look at the attributable risk that each of those risk factors carries if you add them all up together that about 45 percent of the risk of dementia is tied up in those risk factors.

And so what that means is if you could modify those risk factors, that you could then theoretically delay or even prevent 45% of cases of dementia.

Now that sounds exciting.

It doesn't mean that you can get rid of 45% of cases of dementia completely.

What it means is in 45% of people who have dementia, the onset of their illness could have been delayed, maybe only by a few weeks or months, or maybe even prevented if you could correct all those risk factors.

But also you're saying that even if you were able to address every single one of those risk factors,

that would still only affect 45% of cases of Alzheimer's.

And by effect, we don't necessarily mean prevent, we just mean delay, and it might not be a big delay.

So that's a very different picture from this rather chirpy statement that 90% of Alzheimer's can be avoided.

I mean, I am slightly struggling to understand what they have in mind in the interview they gave to the Zoe podcast.

So we have to be careful.

In our book, we said that 90% of Alzheimer's can be potentially prevented.

You know, we live in an age where people are playing around with numbers, and we have to be very careful as scientists.

So there's no direct evidence of that.

Direct evidence says 60%.

Pretty much direct evidence.

But we say that if you have optimal lifestyle elements, which we'll talk about, as much as 90% can be prevented.

Got it.

But you're saying even now, like, there's clear data that 60% could be prevented.

Do you recognize the 60%

number?

Well,

not really, no.

I mean,

the work that we did that was published in The Lancet

was extremely robust and a large number of people all around the world looked very hard at all the data.

Unfortunately the figures presented by the doctors on the Zoe podcast are not bolstered by good data actually looking at Alzheimer's.

Their course seems to promote general brain health, which is important.

but it doesn't take into account many of the risk factors and genetic components that add up together to cause Alzheimer's.

We've only identified a few of the genes that could have an interplay with environmental risks that can cause dementia.

There's nothing too solid.

We put our skepticism to the doctors, and this is what they replied.

While we don't have definitive figures on the exact percentage of Alzheimer's cases that can be prevented, the available data suggests that it is a significant factor.

Our estimate, which we consistently emphasise as a broad extrapolation, ranges from 40% to 90%.

Well, it's certainly true that even on the Zoe podcast, they said that 90% of cases could be prevented and immediately added that there was no direct evidence for that.

So, sure, broad extrapolation.

Everyone agrees that more research is essential.

Our thanks to Professor Rob Howard.

On the 8th of May 2025, the Catholic Conclave elected US Cardinal Robert Prevost as Pope.

Journalists immediately started googling and found that somewhat surprisingly, the new Pope had a maths degree.

Super sleuths on the internet even found a book that Robert Prevost had written with an analysis of the way philosophers have used Bayesian statistics to argue about the existence of God.

The tweet that discovered the Pope's book, Probability and Theistic Explanation, went viral.

So we used our deep connections in the world of statistics and Bayesian discourse to email out an interview request to Robert Prevost on the subject of his book.

Remarkably, despite his busy schedule, he agreed to an interview.

Your Holiness, thank you for granting us an audience.

Welcome to more or less.

Oh, thank you for having me.

So this Pope business.

How do you feel about it?

Well, it has been a wild ride for me.

When he was elected.

I started soon after that receiving congratulatory communication from all over the world

about being elected Pope.

Was that a surprise?

Certainly.

I wasn't expecting it, that's for sure.

And it's just continued.

The confusion, I mean, I've seen sort of internet blogs, you know, where they're sort of scratching their head over is the author of probability and theistic explanation the same person as the pope and uh the confusion continues.

Wait,

you're not the Pope?

No, I'm not.

Though we have the same name, I'm not the Pope.

Ah, well, I'm sure we can find something to talk about anyway.

So who are you?

Well, I am a philosophy professor at Wingate University in Wingate, North Carolina.

And

just to be clear, who wrote the Bayesian analysis of the existence of God?

Was it you or the Pope?

It was me.

Yes.

Well, we do have something to talk about, Ben.

So a Bayesian analysis of the existence of God,

just briefly explain to us what that might involve.

What are you trying to do there?

Well, the way it's used in philosophy of religion has to do with confirmation.

What evidence confirms the existence of God?

Probability are Bayesian theories used to ask questions of traditional arguments, such as the, you know, why is there something rather than nothing?

Or is there evidence of design in the universe?

And so on.

Bayes' rule allows you to calculate how the probability of an event changes in the light of new information.

It was first sketched out in the 18th century by Thomas Bayes and as a cornerstone of rational statistical analysis.

It seems a long way from arguments over the existence or non-existence of God,

but the non-Pope Robert Prevost's theological use, was pretty close to the original aim.

Bayes was a Presbyterian minister, and the introduction to his work argued that the probabilistic approach showed that life must have an intelligent cause, which kept everything running nice and predictably.

Still, before we recommend this approach to the actual Pope, I should point out that Robert's book was actually somewhat critical of the use of Bayesian reasoning in religious arguments.

Do you think that Bayes' theorem is a good way of thinking about whether God exists or not?

Well, it is a good way of sort of illustrating what one believes.

You have to make some subjective judgments using Bayes' theorem.

I mean, these are subjective judgments that can be argued for.

But the real heart of the matter is how strong are those initial sort of valuations of the probabilities.

Bayes' rule is all about how to adjust your initial beliefs in the light of new information.

But if your initial belief is about how likely it is that God exists, then the ball game is all but over before the Bayesian analysis gets going.

In my book, you know, I compare two very respected philosophers who

understand probability theory, Bayes' theorem, and so on, but they come to diametrically opposed positions.

God or no God, you can use the probabilities to argue both ways.

As for the probability of a Catholic American academic having the same name as a Catholic American cardinal who was elected pope, and also having written a book that could plausibly have been written by either, frankly, the Lord only knows.

Robert's just enjoying the moment, although he isn't yet cashing in.

I haven't run out to buy what a mitre to wear.

So I haven't figured out how to monetize it yet.

Though one email said that

the price of my book had exploded on the internet, you know, since it was

since Leo was selected as or elected to be Pope.

Unfortunately, it was an academic imprint and I'm not getting any royalties for it.

So

that's not working for monetizing it.

Our thanks to Robert Prevost, not the Pope, for talking to us.

The Pope is not the only new world leader with a maths background.

The new president of Romania, Nicusaudan, is an incredibly talented mathematician with a PhD in mathematics and two first-place finishes in the International Mathematical Olympiads, where he twice scored 100%.

And the list doesn't end there.

President Trump has recently developed a new concept.

What we're doing is equalizing.

There's a new word that I came up with, which I think is probably the best word we're going to equalize.

Mathematicians around the world would be delighted.

They're already wondering how on earth they coped before the president invented the idea.

That's about it for this week.

If you want to get in touch, please be sure to email moreorless at bbc.co.uk.

And if you want to try some puzzling probability problems, head to bbc.co.uk, search for more or less, and follow the links to the Open University.

We will be back next week.

Until then, goodbye.

More or less was presented by me, Tim Harford.

The producer was Tom Coles, with Nicholas Barrett, Nathan Gower, and Lizzie McNeil.

The production coordinator was Brenda Brown.

Nigel Appleton recorded and mixed the show, and our editor is Richard Varden.

Hi, I'm India Ackerson, and I want to tell you a story.

It's the story of you.

In our series, Child from BBC Radio 4, I'm going to be exploring how a fetus develops and is influenced by the world from the very get-go.

Then, in the middle of the series, we take a deep look at the mechanics and politics of birth, turning a light on our struggling maternity services and exploring how the impact of birth on a mother affects us all.

Then, we're going to look at the incredible feat of human growth and learning in the first 12 months of life.

Whatever shape the journey takes, this is a story that helps us know our world.

Listen on BBC Sounds.

Suffs, the new musical has made Tony award-winning history on Broadway.

We demand to be home.

Winner, best score.

We demand to be seen.

Winner, best book.

We demand to be quality.

It's a theatrical masterpiece that's thrilling, inspiring, dazzlingly entertaining, and unquestionably the most emotionally stirring musical this season.

Suffs, playing the Orpheum Theater, October 22nd through November 9th.

Tickets at BroadwaySF.com.