Tim Harford's Blog, page 45
April 22, 2021
Why we fear blood clots
Wrinkles and grey hairs notwithstanding, I must be younger than I had assumed. Sixty per cent of the adult population of the UK have been vaccinated with at least one dose, but your columnist is not old enough to be one of them. Who knew?
This means I still have the joys of a jab ahead of me, and I can’t wait for the sweet superpower of immunity. All the available vaccines in the UK are hugely effective at preventing severe illness, and they increasingly look as though they greatly reduce transmission too.
And yet, when the needle finally slides into my arm, I’ll have to suppress a nervous gulp. The AstraZeneca vaccine I am likely to receive, developed in my home city of Oxford, has rarely been out of the headlines — most recently because of the suspicion that it may make a rare form of blood clot slightly less rare. The same suspicion has led US authorities to recommend suspension of Johnson & Johnson’s vaccine.
Our gut feelings are powerful. The AlpspiX viewing platform in Bavaria is a cantilevered structure, where a mesh floor reveals an unnervingly large drop. My rational mind tells me it is perfectly safe. My legs and my stomach tell me something else entirely; I find it hard to physically make myself walk out to the end.
The philosopher Tamar Gendler coined the word “alief”, a counterpoint to “belief”, to describe such instincts. I believe the AlpspiX platform is safe; I “alieve” that it is extremely perilous.
And the vaccine? Setting “alief” to one side, I believe it is extremely safe. The clotting side‑effect of the vaccine is rare — so rare that we are still not certain that it exists. It is certainly far too rare to discover in a controlled clinical trial, where a vaccine dose is given to tens of thousands of participants rather than millions.
An educated guess, based on UK data, is that being vaccinated with the AstraZeneca jab carries a one-off risk of death of one in a million — not much higher than the risk of dying in an accident while travelling to a vaccination clinic. If that guess is correct (and it may not be: European data suggest it is higher) then vaccinating the entire UK population with a dose of this particular vaccine would give 67 people fatal blood clots.
That sounds bad — as does any sentence containing the phrase “fatal blood clots”. Yet in the UK the death toll from coronavirus was never below 67 per day between mid‑October and late March — and sometimes headed for 67 per hour. In other words, for the entire winter wave, a single day’s delay to being vaccinated has been riskier than the vaccine itself.
Individual risks vary: young people are at vastly less risk of a fatal dose of Covid-19 and perhaps at somewhat higher risk of vaccine side-effects. Researchers at the Winton Centre for Risk and Evidence Communication have put together an excellent visualisation of the estimated risks, showing that for most people, in most circumstances, the vaccine prevents much more harm than it might cause. But for young people, during a lull in the pandemic, the balance of risks is less clear cut, which is why the British authorities are planning a brief delay to ensure young people receive a different vaccine.
The numbers should be very reassuring. But our emotions do not always respond to numbers. David Ropeik, author of How Risky Is It, Really?, points to a variety of factors that make some risks loom large in the imagination.
The most obvious is salience: in recent weeks, particularly in the UK and EU, there has been saturation coverage of the blood‑clot story, despite the fact that by any measure there have been vastly more deaths from Covid-19 itself. This is understandable — news is news, after all — but it leads our instincts astray. The rational question is, “Statistically speaking, do the benefits of the vaccine outweigh the harms?”, but the easier question is, “Can I easily call those dangers to mind?”
A second factor is control. Driving is more dangerous than flying, but most people fear flying more: they feel they can protect themselves while driving, but not while flying. To an extent, that is true — and also true for Covid-19. There are steps we can all take to reduce the risk of infection, and there is nothing we can do to reduce the risk of a fatal reaction to a vaccine. The fact remains, however, that planes and Covid-19 vaccines are very safe — and cars and Covid-19 infections are not.
A third factor is trust. I know about Boris Johnson’s track record with truth, and am far from reassured whenever I hear him declare his confidence in the AstraZeneca vaccine.
Scientists, fortunately, remain more widely trusted. Professor Sir David Spiegelhalter of the Winton Centre tells me that the announcement last week was a “tour de force of risk communication”, largely because the politicians were nowhere to be seen. Instead, scientists and medical officials presented risks and benefits in a sober way, doing a lot to earn the trust of viewers. That counts for a great deal. Ultimately, our view of vaccines depends not on the data, but on something more primal: do I trust these people to have my best interests at heart?
The data tell me that the vaccine is not only safe but a life saver for me and for those around me. I’ll still be nervous when I finally get to the clinic, but I can’t imagine it will be nearly as bad as the AlpspiX platform. And if I had to walk out on that platform to save a life? I wouldn’t like it, but I’d do it in a heartbeat.
Written for and first published in the Financial Times on 14 April 2021.
The paperback of “How To Make The World Add Up” is out on 6th May. US title: “The Data Detective”.
“Nobody makes the statistics of everyday life more fascinating and enjoyable than Tim Harford.”- Bill Bryson
“This entertaining, engrossing book about the power of numbers, logic and genuine curiosity”- Maria Konnikova
I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.
April 19, 2021
The best books and tweeps about data, long Kahneman interview, and other thoughts
Next up is Julia Galef’s The Scout Mindset which looks terrific but which I have not yet read. Meanwhile I have curated a list of the best books for thinking about data, and – seperately – some recommendations of twitter people to follow on the subject of maths and in particular maths communication and education.
In other adventures, I gave a talk – with plenty of conversation and interaction – at the World Bank & IMF, kindly hosted by the IMF library.
If you don’t have two hours to spare I suggest you change that, because Scott Barry Kaufman’s long interview with Danny Kahneman is well worth your attention. Kahneman’s interesting new book Noise gets a look-in but the podcast ranges much more widely, is fascinating and often quite moving.
Finally, Peter Sims argues that “a new renaissance is underway“; Peter’s book, Little Bets, is a stone cold classic.
“Nobody makes the statistics of everyday life more fascinating and enjoyable than Tim Harford.”- Bill Bryson
“This entertaining, engrossing book about the power of numbers, logic and genuine curiosity”- Maria Konnikova
I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.
April 15, 2021
Cautionary Tales – Demonising Dungeons & Dragons
How the hunt for a missing teen saw a role-playing game denounced as a demonic and deadly pursuit.
When James Dallas Egbert III was reported missing from his college dorm – one of America’s most flamboyant private detectives was summoned to solve the case. “Dallas” had many of the same problems that most teenagers face – but P.I. William Dear feared that he had fallen under the evil spell of a mysterious and sinister game…. Dungeons & Dragons.
The global panic about the dangers the role-playing game posed to impressionable young minds may seem quaint 40 years on – but again and again we show how fearful we are of creative endeavours we don’t quite understand.
Cautionary Tales is written by me, Tim Harford, with Andrew Wright. It is produced by Ryan Dilley and Marilyn Rust.
The sound design and original music is the work of Pascal Wyse. Julia Barton edited the scripts.
Thanks to the team at Pushkin Industries, Mia Lobel, Jacob Weisberg, Heather Fain, Jon Schnaars, Carly Migliori, Eric Sandler, Emily Rostek, Maggie Taylor, Daniella Lakhan and Maya Koenig.
Further reading and listening
David Ewalt’s Of Dice and Men is a fun and accessible history of Dungeons & Dragons. Jon Peterson’s Playing at the World is a more scholarly and hugely detailed treatment of the same material. Both contain useful accounts of Dallas Egbert’s disappearance.
Another important source – including for most of the dialogue in this episode – is William Dear’s vivid description of the case, The Dungeon Master.
Contemporary media reports were useful. “Tunnels are Searched for Missing Student” (New York Times, 8 Sep 1979), “A Brilliant Student’s Troubled Life and Early Death” (New York Times, 25 Aug 1980), and Carla Hall’s “Into the Dragon’s Lair” (Washington Post 28 Nov 1984).
The American Hysteria Podcast “Satanic Panic: Part One” offers another account of the case.
What have we learnt from a year of Covid?
We are now about a year into the ohmygosh-this-is-for-real stage of the pandemic. A time, perhaps, for taking stock of the big decisions — and whether they were wise.
To my mind, there were two big calls to be made. The first: was this virus a deadly enough threat to merit extraordinary changes to life as we know it? The second: should those changes be voluntary or a matter for politicians, the courts and the police?
The UK wavered over the first decision — long enough to ensure that the country suffered one of the deadliest first-wave outbreaks in the world. But in the end, the decision was made: this wasn’t just like a bad flu, which we should take on the chin. It was simply too dangerous to keep calm and carry on.
I have always suspected that this realisation was sparked by the terrifying footage from overwhelmed Italian hospitals, but modelling also played a part. An infamous working paper, “Report 9”, published just over a year ago by the Covid-19 Response Team at Imperial College, predicted: “In the (unlikely) absence of any control measures or spontaneous changes in individual behaviour . . . 81% of the GB and US populations would be infected.” If so, more than 500,000 people would die in the UK alone.
I have read several explanations of why this report was so badly mistaken. That is odd — I re-read it this week and it doesn’t seem mistaken at all. The researchers got the big picture right: Covid-19 was highly infectious, killed about 1 per cent of the people infected in the UK and thus could kill a huge number of people if not stopped. Most of those who died would be elderly.
We have not, thank goodness, seen 500,000 deaths. But we might well reach 150,000. Most of those deaths were caused by two terrifyingly rapid waves of infection. Had we shrugged our collective shoulders and done nothing but make more coffins, 500,000 deaths would surely have been the result.
The Imperial report also correctly suggested that lockdowns might have to be repeated almost indefinitely until a vaccine became available. I didn’t want to believe it at the time, but it gave us a glimpse of the future: rolling lockdowns for more than a year.
The report’s mention of “control measures or spontaneous changes in individual behaviour” raises the second big choice we collectively made — with the media, politicians, public health officials and police all playing a role. The question was how much to trust ordinary citizens to make sensible decisions. Our answer: not much.
Read the newspaper headlines and you’d conclude that we were all panicky, selfish fools: too scared of a virus in a faraway country (those “don’t overreact” articles from early 2020 have not aged well); hoarding all the masks and loo paper; and performing acts of outrageous selfishness such as going to the beach or the park.
This narrative was unhelpful in several ways. First, people are influenced by each other — an idea sometimes termed “social proof”. If you show us images of selfish covidiots, we are more likely to be selfish; show us noble altruists and we aspire to be like them. Second, because the shaming focused on publicly visible behaviour, people were blamed for doing something quite safe — going outside. Third, if we believe people are foolish and selfish, we have to rely on writing and then enforcing strict rules about what is and is not allowed.
Such rules are inevitably blunt. They implicitly endorse much that they should not (such as sitting 2.1 metres apart from someone in a poorly ventilated office or pub), while banning all sorts of things that should be permitted. Last spring, I saw the police admonishing a lady sitting alone in the middle of a meadow. Had she been doing sit-ups, her behaviour would have been allowable as daily exercise — but she was reading a book and was thus a lawbreaker. Absurd.
I suspect — but cannot prove — that a lighter touch would have prevented more Covid with less collateral damage. Pure voluntarism might not have been enough, but you can get a long way with altruism, social pressure and clear guidance.
Japan’s advice — to avoid the “Three Cs” of closed spaces, crowded places and close contact — is far more memorable to me than whatever strange combination of households, settings and exemptions the authorities in my own country are currently allowing. (Let’s not even start on the excuses made for the behaviour of Dominic Cummings.)
Nowhere was this clearer than in the government’s catastrophic handling of Christmas. It issued an incomprehensible tangle of rules allowing a three-household “Christmas bubble”, basked in headlines such as “Boris Johnson battles experts to save Christmas” and finally backpedalled at the last moment. The result was that many families made dangerous plans to spend Christmas with elderly relatives on the assumption that they must be safe because they were legal, then felt resentment at the change. Much of the damage was already done; most days in January had more than 1,000 deaths.
There is every reason to believe that vaccination is making short work of the pandemic in the UK, but it is always worth learning lessons. I’ll remember to trust the competence of the government a little less, to trust mathematical models a little more and to have some respect for the decency of ordinary people.
Written for and first published in the Financial Times on 19 March 2021.
“Nobody makes the statistics of everyday life more fascinating and enjoyable than Tim Harford.”- Bill Bryson
“This entertaining, engrossing book about the power of numbers, logic and genuine curiosity”- Maria Konnikova
I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.
April 13, 2021
Thumbs up from the US Air Force, and other news
Cautionary Tales – why organisations squander good ideas… I’ve been so pleased at all the kind comments from around the world about the new season of Cautionary Tales. If you haven’t sampled it, please do so. I love working on the scripts and the narration, but I’m always stunned by the final mix, with spectacularly gifted actors (Helena Bonham Carter, Jeffrey Wright, Alan Cumming, Archie Panjabi, Russell Tovey and a cast of thousands…)
How splendid, then, to get an endorsement from General Charles Q. Brown, chief of staff of the US Air Force. You never know who is listening…
How To Make The World Add Up – In Paperback If you are anywhere outside the US / Canada / Guam, the paperback edition of “How To Make The World Add Up” is imminent and I would be pathetically grateful for pre-orders (Amazon, Bookshop), which are very helpful in ensuring that bookshops stock up, reviewers pay attention, and so on. If you are planning to grab the paperback, THANK YOU – and please consider pre-ordering.
TechTonic interview Mark Hurst interviewed me on the TechTonic podcast / radio show – Mark is a fascinating thinker and you might enjoy the conversation here.
Getting Things Done This week I re-read David Allen’s modern classic Getting Things Done, partly in preparation for a talk I’m giving to GTD enthusiasts about my own work habits. The book needs no introduction from me, I’m sure, but I do wholeheartedly recommend it. It’s intriguing to re-read: there’s a lot of complexity in the book, and one always picks up something new. The key insight I found myself highlighting was the importance of clarifying. I’ve been GTDing for a long time, but whenever ‘stuff’ is piling up, the fundamental problem is usually a failure to be clear about what it really is and what the next action is.
Anyway: my next action is to sketch the outline of an FT Magazine cover story. And your next action, I hope, is to pre-order How To Make The World Add Up…
April 12, 2021
Announcing the paperback publication of “How To Make The World Add Up”
I’m delighted to announce that the paperback edition of “How To Make The World Add Up” is imminent – it will be published on 6th May in the UK as well as Australia, India, Ireland, New Zealand, Singapore, South Africa , and indeed anywhere else outside the US and Canada.
(Your daily reminder, with my apologies, that in the US & Canada the same book has a different title: The Data Detective.)
The book tries to distill everything I’ve learned in fifteen years of writing columns and nearly that long in presenting More or Less. I argue that numbers are an essential tool for making sense of the world – and every one of us has the ability to make sense of the statistical claims all around us. By asking a few simple questions of the numbers, and of ourselves, we can make the world make sense.
The book is full of stories and examples, from the nurse who started a public health revolution with a pie chart to the forger who fooled the experts – and the Nazis.
I’m very proud of the book and was delighted with how the hardback edition was received – it was the number one Sunday Times business bestseller in December. A Christmas Number One!
Alas, the bad news is that the hardback sold out over and over again. Lots of people who were interested in buying the book will, I fear, have shrugged and given up. So the paperback launch feels like a second chance for them, for me and for the book.
I know that you’re thinking, “Tim, what can I do to help?”
I’m really glad you asked. Pre-orders are incredibly helpful in prodding bookshops to stock up, and in pushing the book onto the all-important bestseller lists. So if you plan to buy the book, please do it straight away! You can pre-order on Bookshop or Amazon – or stroll down to your local bookshop (they re-open TODAY in the UK) and place an order.
If you bought the hardback and enjoyed it, thank you so much – and consider pre-ordering a paperback for a friend. Or just spread the word. Thank you.
April 8, 2021
Cautionary Tales – Number Fever; How Pepsi Nearly Went Pop
Pepsi twice ended up in court after promotions went disastrously wrong. Other big companies have fallen into the same trap – promising customers rewards so generous that to fulfil the promise might mean corporate bankruptcy.
Businesses and customers alike are sometimes blinded by the big numbers in such PR stunts – but it’s usually the customers, not the businesses, who end up losing out.
Cautionary Tales is written by me, Tim Harford, with Andrew Wright. It is produced by Ryan Dilley and Marilyn Rust.
The sound design and original music is the work of Pascal Wyse. Julia Barton edited the scripts.
Thanks to the team at Pushkin Industries, Mia Lobel, Jacob Weisberg, Heather Fain, Jon Schnaars, Carly Migliori, Eric Sandler, Emily Rostek, Maggie Taylor, Daniella Lakhan and Maya Koenig.
Further reading and listening
Numerous contemporary news reports tell the story of Number Fever – for example, this piece in the Los Angeles Times by Bob Drogin.
After recording the script, I discovered an excellent long read in Bloomberg by Jeff Maysh. It was too late to help us make this Cautionary Tale but it is the most comprehensive piece of reporting on the subject and highly recommended.
David Philips tells his pudding story here, the exploits of Bananaman are here, while the Hoover fiasco is relayed by The Hustle as “The Worst Sales Promotion In History“. Maybe.
Here is a legal analysis of the fighter jet case, while Tim Silk and Chris Janiszewski have an academic paper on “Managing Mail-in Rebate Promotions“.
Matt Parker’s delightful book Humble Pi tells the story of the Pepsi Points Harrier ‘offer’; John Allen Paulos’s Innumeracy is a modern classic.
April 7, 2021
Technology has turned back the clock on productivity
Has the economic clock started to run backwards? The defining fact of economic history is that, over time, humans have been able to produce vastly more of whatever goods and services they value.
In The Wealth of Nations, Adam Smith had no doubts that the foundation of this dizzying economic growth was specialisation — the division of labour. Yet much modern knowledge work is not specialised at all. Might that explain why we all seem to be working so hard while fretting about getting so little done?
As Philip Coggan writes in his epic history, More: The 10,000 Year Rise of the World Economy, Smith’s 1776 book was not the first to note the productivity gains that resulted from specialisation. Xenophon was making similar remarks in 370 BCE.
But why does the division of labour improve productivity? Smith pointed to three advantages: workers perfected specific skills; they avoided the delay and distraction of switching from one task to another; and they would use or even invent specialised equipment.
The modern knowledge worker fits uneasily into this picture. Most of us don’t use specialised equipment: we use computers capable of doing anything from accountancy and instant messaging to filming and editing video. And while some office jobs have a clear production flow, many do not: they are a watercolour blur of one activity bleeding into another.
I first noticed this reversal 20 years ago. At the time, economists were puzzling over why computers did not seem to have boosted productivity. Meanwhile, I had an office job with a bewildering variety of responsibilities. Sometimes I was doing research and analysis, sometimes I was figuring out what font to use on a PowerPoint slide.
Office work is becoming ever more generalist. Everyone does their own typing nowadays, and many people do their own expense claims, design their own presentations and manage their own diaries. We all have access to user-friendly software, so why not?
In 1992 the economist Peter Sassone published a study of workflow in large US corporate offices. He found that the more senior a person was, the more likely they were to do a bit of everything. Administrative assistants did not do management, but managers did do administration. Sassone called this “the law of diminishing specialisation”.
This law of diminishing specialisation is surely stronger today. Computers have made it easier to create and circulate written messages, to book travel, to design web pages. Instead of increasing productivity, these tools tempt highly skilled, highly paid people to noodle around making bad slides. Variety is pleasant, and it is all very well to bake sourdough or knit cardigans as a hobby — but a high-paid office job is no place for amateur hour.
Is this a real problem? It might be. Adam Smith describes a pin factory employing 10 specialists producing 48,000 pins a day. A single generalist, operating without specialised equipment, “could scarce, perhaps, with his utmost industry, make one pin in a day, and certainly could not make twenty”. Nobody would expect a 4,800-fold productivity increase if modern knowledge workers spent a little less time coordinating meetings over email and a little more time focusing on the key aspects of their jobs. But even a twofold increase would be worth taking seriously.
Cal Newport’s new book, A World Without Email, is searing on this point. Examining scientific management studies from the early 20th century, Newport makes the case that manufacturers analysed and fixed their aimless processes a century ago. The gains were dramatic.
For example: at the Pullman factory complex near Chicago, people from various departments would wander into the brass works and pester the metalworkers until they got what they needed. After a systematic overhaul, many clerks were hired as gatekeepers and to plan and schedule work. Productivity soared.
Newport argues that knowledge work is long overdue a similar rethink. How often is office work assigned and prioritised by random pestering? Certain disciplines, including producing a daily newspaper, have developed a clear workflow that doesn’t depend on long email chains. A lot of knowledge work, however, is still in the “wander in and pester” stage. Newport argues that managers and administrators alike should be protecting specialists from distraction, and that we can do much better if we rethink our processes from the ground up.
Turning the office into another assembly line doesn’t sound fun. Smith, famously, fretted that repetitive, simple specialisation would lead a worker to become “as stupid and ignorant as it is possible for a human creature to become”. In an 18th-century pin factory, perhaps, but less so for 21st-century knowledge work.
A very different passage in The Wealth of Nations is closer to the mark: “Men are much more likely to discover easier and readier methods of attaining any object, when the whole attention of their minds is directed towards that single object, than when it is dissipated.”
No one is longing for a return to the pin factory. Modern knowledge work is nothing like pin-making, and the variety that comes from a hyperactive reliance on email is not the kind that allows us to flourish. My own ideal is what I call “slow-motion multitasking”: have a variety of projects in progress, allowing them to cross-fertilise each other. But do one thing at a time.
Written for and first published in the Financial Times on 12 March 2021.
“Nobody makes the statistics of everyday life more fascinating and enjoyable than Tim Harford.”- Bill Bryson
“This entertaining, engrossing book about the power of numbers, logic and genuine curiosity”- Maria Konnikova
I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.
April 5, 2021
In conversation with David Spiegelhalter, and the power of checklists
A few weeks ago Professor Sir David Spiegelhalter and I sat down to talk about “what do the numbers mean?”, courtesy of the Cambridge Festival. The conversation is now online – enjoy!
I am popping with delight at the news that I have been shortlisted for Journalist of the Year by the Wincott Foundation. Some of the most wonderful business and economics journalists in the world have won this award, and I’ve never been close before. I’m honoured.
The book grabbing my attention this week is Atul Gawande’s The Checklist Manifesto. It’s been on my bookshelf for years and I’ve taken delayed gratification a little too far. It is, as expected, a superlative read, full of good stories and fascinating examples, and Gawande makes a powerful case for the effectiveness of using checklists in a suprising range of circumstances. He ranges from rock concerts through restaurant kichens and the building of a skyscraper – and of course, medicine. One of the surprising insights was the use of a communication checklist: the idea of ensuring that the right people talk to each other at the right moments. Strongly recommended.
“Nobody makes the statistics of everyday life more fascinating and enjoyable than Tim Harford.”- Bill Bryson
“This entertaining, engrossing book about the power of numbers, logic and genuine curiosity”- Maria Konnikova
I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.
April 1, 2021
Cautionary Tales – The Curse of Knowledge meets the Valley of Death
How assuming others understand exactly what we are thinking gets people killed.
Why were soldiers on horseback told to ride straight into a valley full of enemy cannon? The disastrous “Charge of the Light Brigade” is usually blamed on blundering generals. But the confusing orders issued on that awful day in 1854 reveal a common human trait – we often wrongly assume that everyone knows what we know and can easily comprehend our meaning.
Starring Helena Bonham Carter as Florence Nightingale.
Cautionary Tales is written by me, Tim Harford, with Andrew Wright. It is produced by Ryan Dilley and Marilyn Rust.
The sound design and original music are the work of Pascal Wyse. Julia Barton edited the scripts.
Thanks to the team at Pushkin Industries, Mia Lobel, Jacob Weisberg, Heather Fain, Jon Schnaars, Carly Migliori, Eric Sandler, Emily Rostek, Maggie Taylor, Daniella Lakhan and Maya Koenig.
Further reading and listening
Two authoritative accounts of the Light Brigade’s charge are The Charge by Mark Adkin and Hell Riders by Terry Brighton.
Steven Pinker’s The Sense of Style describes the “curse of knowledge”, and Elizabeth Newton’s reserach paper is “The Rocky Road From Actions to Intentions“.
Power distance and the Korean Air Flight 801 crash are dissected in Malcolm Gladwell’s Outliers.
