After nearly 16,000 cases disappeared off coronaviruses spreadsheets, we ask what went wrong. How common are lasting symptoms from Covid-19? If you survey people about the death toll from Covid, they’ll make mistakes. What do those mistakes teach us? Pedants versus poets on the subject of exponential growth. And we dive deep into the unholy marriage of mathematicians, gamblers, and actuaries at the dawn of modern finance.

Case counts in perspective, a suspect stat from the US, and life lessons from insects.

A scary government graph this week showed what would happen if coronavirus cases doubled every seven days. But is that what’s happening? There’s much confusion about how many Covid test results are false positives - we explain all. Plus, do coffee and pregnancy mix? And the Queen, Mao, and Gandhi go head to head: who is on the most stamps and coins?

Tim Harford speaks to Israeli researcher, Tomer Hertz, about how the mathematical magic of pool testing could help countries to ramp up their Covid-19 testing capacity.

Amid reports of problems with coronavirus testing across the UK, we interrogate the numbers on laboratory capacity. Does the government’s Operation Moonshot plan for mass testing make statistical sense? Has the UK been taking more refugees from outside the European Union than any EU country? We explore the connection between socio-economic status and Covid deaths. And we do the maths on a mascara brand’s bold claim about emboldening your eyelashes.

A jump in the number of UK Covid-19 cases reported by the government has led to fears coronavirus is now spreading quickly again. What do the numbers tell us about how worried we should be? Plus a guide to balancing life’s risks in the time of coronavirus, the government’s targets on test and trace, and a suspicious statistic about the speed of jelly-fish.

As children return to school in England and Wales, we hear about what we know and what we don’t when it comes to Covid-19 risks in school settings. What do the numbers tell us about how well test and trace is working? Will reopening universities really kill 50,000 people? Are the UK’s figures on economic growth as bad as they look? And is maths real? When someone goes viral asking maths questions on social media, More or Less finds answers.

Donald Trump says allowing the emergency use of blood plasma therapy for coronavirus patients will save “countless lives” and is “proven to reduce mortality by 35%”. We look at the evidence. Amid talk of coronavirus being back on the rise in the UK, what does the data show? Could screening for breast cancer from the age of 40 save lives? And can it really be true than one in five women in 18th century London made a living selling sex?

We unpick the A-level algoshambles, discover why 1.3 million Covid tests disappeared from the government's statistics last week, and for reasons that may become clear, we examine the chance of being hit by a bus. Plus, what does poker teach us about the role of randomness in our lives?

Autocratic leader Alexander Lukashenko claims to have won a landslide in the country’s presidential elections. But how can we know what really happened? Tim Harford delves into the numbers behind the widely-questioned election result, with Dr Brian Klaas and political analyst Artyom Shraibman.

Covid-19 cases are rising in the UK - is it a sign of a second wave of the virus? We’re picking apart the data and asking how concerned we should be both now and as autumn approaches. Scotland is undercounting Covid deaths, England is overcounting them: we’ll ask why and whether the problems will be fixed. Celebrity chef Jamie Oliver claims over a quarter of all the fruit and veg kids eat is in the form of pizza, can this be true? Plus, as some people are blaming obesity for the severity of the coronavirus outbreak in the UK, we’ll find out how big a difference it really makes.

One More or Less listener has heard that if all the ice in Antarctica melted, global sea levels would rise by 70 metres. But it would take 361 billion tonnes of ice to raise the world's sea levels by just 1 millimetre. So how much ice is in Antarctica? And in the coming years, what impact might temperature changes have on whether it remains frozen?(Gentoo penguins on top of an iceberg at King George Island, Antarctica January 2020. Credit: Alessandro Dahan/ Getty Images)

Do we have enough data to know what’s happening on the continent? We talk to Dr Justin Maeda from the Africa Centre for Disease Control and Ghanaian public health researcher Nana Kofi Quakyi about tracking Africa’s outbreak. Producer: Jo Casserly Picture: Volunteers wait to feed local people during the weekly feeding scheme at the Heritage Baptist Church in Melville on the 118 day of lockdown due to the Covid-19 Coronavirus, Johannesburg, South Africa, 2020. Credit: EPA/KIM LUDBROOK

Tim Harford speaks to Steven Johnson about William Farr and the birth of epidemiology in the 1800s.

Tim Harford talks to statistician Ola Rosling about his research into misconceptions about Covid-19. And an update on the epidemic in the US.

Unlike its Nordic neighbours, Sweden never imposed a lockdown to stem the spread of coronavirus. Tim Harford speaks to statistician Ola Rosling to find out what the results have been.Presenter: Tim Harford Producer: Jo CasserlyPicture: A woman wearing a face mask stands at a Stockholm bus stop where a sign reminds passengers to maintain a minimum social distance. Sweden 25 June 2020. Credit: EPA/ Stina Stjernkvist

Are cases really rising in the US or are they just testing more? Tim digs into the data.

The UK has suffered one of the worst outbreaks of coronavirus anywhere in the world. We’ve been tracking and analysing the numbers for the last 14 weeks, and in the last programme of this More or Less series, we look back through the events of March 2020 to ask why things went so wrong - was it bad decision-making, bad advice, or bad luck?

The steroid Dexamethasone has been hailed a “major breakthrough” in the treatment of Covid-19. But what does the data say? Plus, why haven’t mass protests led to a second wave?

As lockdown eases, why hasn't there been a spike in infections? We get a first look at the evidence for the much-trumpeted Covid-19 treatment, Dexamethasone. Stephanie Flanders tells us what’s happening to the UK economy. Keir Starmer says child poverty is up; Boris Johnson says it’s down, who's right? Plus which children are getting a solid home-school experience, and who is missing out?

Some countries are requiring new arrivals to self-isolate, a policy designed to stop infection spreading from areas of high prevalence to low prevalence. Tim Harford and Ruth Alexander find out which countries have the highest rate of Covid-19 infection. Plus, is it really true that the coronavirus mostly kills people who would die soon anyway?

The UK has introduced new rules requiring all people arriving in the country to self-isolate for 14 days. But given the severity of the UK’s outbreak can there be many places more infectious? Is it true that Covid-19 mostly kills people who would die soon anyway? The first figures are out showing how England’s Test and Trace programme is performing, but they contain a mystery we’re keen to resolve. And we play with some mathematical puzzles, courtesy of statistician Jen Rogers.

At the start of March the government's Chief Scientific Adviser Sir Patrick Vallance said that the UK’s coronavirus outbreak was four weeks behind the epidemic in Italy. This ability to watch other countries deal with the disease ahead of us potentially influenced the decisions we made about which actions to take and when, including lockdown. So was he right?

What difference does a metre make? The World Health Organisation recommends that people keep at least 1 metre apart from each other to stop the spread of Covid-19, but different countries have adopted different standards. The US Centers for Disease Control and Prevention recommends staying six feet apart - that’s just short of 2 metres; in the UK, the rule is 2 metres. But all this has a big impact on the way businesses and societies get back to work. Tim Harford investigates the economic costs and conundrums of keeping our distance in a post-lockdown world.How can we avoid infection spreading again, while getting on with life?

As lockdowns begin to lift the government is relying on testing and contact tracing programmes to prevent a second wave of Covid-19 infections. But how accurate are the swab tests used to diagnose the disease? The UK Statistics Authority has criticised the government for the way it reports testing figures, saying it’s not surprising that these numbers “are so widely criticised and often mistrusted.” We take a look at how the government achieved its target of developing a daily testing capacity of 200,000 by the end of May. Can we really have only 60 harvests left in the world? Plus, the very pleasant Hugh Fearnley Whittingstall has a pleasant pheasant question for us.

More than 35,000 people in the UK have now officially died from Covid-19, but what does the data show about whether this wave of the epidemic is waning? We ask who respects lockdown, who breaks it, and why?Our listeners are astounded by how many people allegedly flew into the UK in the first three months of the year - we’re on the story. We look at the performance of the Scottish health system on testing. And some pub-quiz joy involving a pencil.

A listener asks if there can really only be 60 harvests left in Earth's soil. Are we heading for an agricultural Armageddon? Plus we meet the parrots who are the first animals, outside humans and great apes, to be shown to understand probability.(image: Kea parrots in New Zealand)

Risk expert David Spiegelhalter discusses whether re-opening some schools could be dangerous for children or their teachers. We ask what’s behind Germany’s success in containing the number of deaths from Covid-19. Many governments across the world are borrowing huge sums to prop up their economies during this difficult time, but with everyone in the same boat who are they borrowing from? Plus we revisit the UK’s testing figures yet again and meet some statistically savvy parrots.

As lockdowns start to lift, many countries are relying on social distancing to continue to slow the spread of coronavirus. The UK says we should stay 2 metres apart, the World Health Organisation recommends 1 metre, Canada six feet. So where do these different measurements come from? Plus, governments around the world are trying to prop up their economies by borrowing money. But with everyone in the same situation, where are they borrrowing from?

R is one of the most important numbers of the pandemic. But what is it? And how is it estimated? We return to the topic of testing and ask again whether the governments numbers add up. As the government encourages those who can’t work at home to return to their workplaces - we’re relying on social distancing to continue to slow the spread of the virus. But where does the rule that people should stay 2 metres apart come from? And is Vitamin D an under-appreciated weapon in the fight against Covid-19?

The question of just how dangerous Covid-19 really is, is absolutely crucial. If a large number of those who are infected go on to die, there could be dreadful consequences if we relaxed the lockdowns that have been imposed across much of the world. If the number is smaller, for many countries the worst might already be behind us.But the frustrating thing is: we’re still not sure. So how can we work this crucial number out?

The Health Minister Matt Hancock promised the UK would carry out 100,000 coronavirus tests a day by the end of April. He claims he succeeded. Did he? The question of just how dangerous the new coronavirus really is, is absolutely crucial. If it’s high, there could be dreadful consequences if we relaxed the lockdowns. So why is the fatality rate so difficult to calculate? Is it true that being obese makes Covid-19 ten times more dangerous? And whatis injuring more kids in lockdown, trampolines or Joe Wicks’ exercises?

With much of the world’s population staying indoors, there are fewer cars on the roads, planes in the skies and workplaces and factories open. Will this have an impact on climate change? Plus as the streets become quieter, is it just us, or have the birds begun to sing much more loudly?

We continue our mission to use numbers to make sense of the world - pandemic or no pandemic. Are doctors from ethnic minority backgrounds disproportionately affected by Covid-19? Was the lockdown the decisive change which caused daily deaths in the UK to start to decrease? With much of the world’s population staying indoors, we ask what impact this might have on climate change and after weeks of staring out of the window at gorgeous April sunshine, does cruel fate now doom us to a rain-drenched summer? Plus, crime is down, boasts the home secretary Priti Patel. Should we be impressed?

Many articles in the media compare countries with one another - who’s faring better or worse in the fight against coronavirus? But is this helpful - or, in fact, fair?Tim Harford and Ruth Alexander discuss the limitations that we come across when we try to compare the numbers of Covid-19 cases and deaths in different countries; population size, density, rates of testing and how connected the country is all play a role.

John Horton Conway died in April this year at the age of 82 from Covid-19 related complications. An influential figure in mathematics, Conway’s ideas inspired generations of students around the world. We remember the man and his work with mathematician Matt Parker and Conway’s biographer Siobhan Roberts.

We compare Covid-19 rates around the world. Headlines say NHS staff are dying in large numbers, how bad is it? And is it just us, or have the birds started singing really loudly?

Scientific models disagree wildly as to what the course of the coronavirus pandemic might be. With epidemiologists at odds, Tim Harford asks if professional predictors, the superforecasters, can offer a different perspective.(Image: Coronovirus graphic/Getty images)

Do face masks stop you getting coronavirus? You might instinctively think that covering your mouth and nose with cloth must offer protection from Covid-19. And some health authorities around the world say people should make their own masks. But expert opinion is divided. Tim Harford and Ruth Alexander unpick the arguments.

Is the coronavirus related death count misleading because of delays in reporting? Do face masks help prevent the spread of the virus? Was a London park experiencing Glastonbury levels of overcrowding this week? And after reports of condom shortages, we ask whether there’s any evidence that we’re nine months away from a lockdown-induced baby boom. Plus in a break from Covid-19 reporting we ask a Nobel-prize winner how many Earth-like planets there are in existence.

Tim Harford and Ruth Alexander examine the statistics around the world to see if more men are dying as a result of Covid-19, and why different sexes would have different risks. Plus is it true that in the US 40% of hospitalisations were of patients aged between 20 and 50?

This week, we examine criticisms of Imperial College’s epidemiologists. We ask how A-Level and GCSE grades will be allocated, given that the exams have vanished in a puff of social distancing. Adam Kucharski, author of The Rules of Contagion, tells us about the history of epidemiology. We look at the supermarkets: how are their supply chains holding up and how much stockpiling is really going on. And is coronavirus having a different impact on men than on women?

Professor Sir David Spiegelhalter, Chair of the Winton Centre for Risk and Evidence Communication, puts the risks of Covid-19 into perspective. He found that the proportion of people who get infected by coronavirus, who then go on to die increases with age, and the trend matches almost exactly how our background mortality risk also goes up. Catching the disease could be like packing a year’s worth of risk into a couple of weeks.(Mathematician and Risk guru, Professor Sir David Spiegelhalter at the University of Cambridge. Credit: In Pictures Ltd./Corbis via Getty Images)

We’ve dedicated this special episode to the numbers surrounding the Coronavirus pandemic. Statistical national treasure Professor Sir David Spiegelhalter put the risks of Covid-19 into perspective. We ask whether young people are safe from serious illness, or if statistics from hospitalisations in the US show a high proportion of patients are under 50. We try to understand what the ever-tightening restrictions on businesses and movement mean for the UK’s economy, and we take a look at the mystery of coronavirus numbers in Iran.Presenter: Tim Harford

Last week, while schools and businesses across Europe closed in an attempt to halt the spread of Coronavirus the UK stood alone in a more relaxed approach to the pandemic; letting people choose whether they wanted to go to work, or socially distance themselves. This week, things have changed. Schools are closing for the foreseeable future and exams have been cancelled. The British government says their change of heart was based on the work scientists like Christl Donnelly from Imperial College London and the University of Oxford. So what has Christl found that has caused such concern? (Image: A lollipop lady helps children cross the road in Glasgow. Credit: EPA/Robert Perry)

Does Iran have a lot more covid-19 cases that its figures suggest?

Every winter its the same, someone will tell you to put a hat on to save your body from losing all of its heat. But how much heat do you actually lose from your head? We take you on a journey from arctic conditions to a hot tub in Canada to explain why there might actually be more than one answer... Presenter: Tim Harford Producer: Leoni Robertson and Lizzy McNeill

Does watching 30 minutes of Netflix have the same carbon footprint as driving four miles?

Dipping into the archive for stories on the art of prediction and wood burner pollution