Blogs

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was produced by the Winton programme for the public understanding of risk based in the Statistical Laboratory in the University of Cambridge. The aim was to help improve the way that uncertainty and risk are discussed in society, and show how probability and statistics can be both useful and entertaining.

Many of the animations were produced using Flash and will no longer work.

Exploring the language of chance in a sensitive context

What words are appropriate when describing the unavoidable unpredictability of real life – what we might casually call ‘chance’?

The risks of Big Data – or why I am not worried about brain tumours.

In a careful study published last week, Socioeconomic position and the risk of brain tumour: a Swedish national population-based cohort study, the authors examined the association between the socio-economic status of men and women in Sweden with diagnosis of brain tumours over 18 years. One of the main findings is shown below.

The risks of trying to be funny

I’ve had a lot of publicity over the last few days, but none of it was welcome. It arose from the story below from the Daily Telegraph of June 6 with the headline “Britons are having less sex, and Game of Thrones could be to blame, says Cambridge professor

game-thrones-telegraph.jpg

The importance of what you don’t see

Remember all those autism stories over the last few weeks? You don’t? There’s a reason for that.

Medicine, poison, poison, poison, ……

Yesterday the Chief Medical Officer announced new guidelines for alcohol consumption. The Summary says,

The proposed guidelines and the expert group report that underpins them, have been developed on the basis of the following principles:

Jeremy Hunt, the Guardian, and the importance of getting the stats right

On Thursday November 19th the printed version of the Guardian had the headline “Experts dispute Hunt's claim on weekend hospital treatment“ [online version here]. But it was not only Health Secretary Jeremy Hunt who gave a misleading statement – the Guardian also made a serious error about statistics.

HRT, breast cancer, and the framing of risks

The way that risks are 'framed' can make a big impression on their apparent magnitude. The controversy following the recent report by NICE on hormone replacement therapy (HRT) provides a fine example.

Is it fair that a single bad outcome should label a surgeon as an outlier?

Surgeons are increasingly subject to statistical monitoring, and named results may be made publicly available. But consider a surgeon in a low-risk specialty who has had a successful and blameless career, until a combination of circumstances, possibly beyond their control, contribute to a single patient dying. They then find they are officially labeled as an ‘outlier’ and subject to formal investigation, all because of a purely statistical criterion. Is this fair?

Why live interviews are a particular challenge for statisticians.

I like doing live interviews for radio or TV – it’s exciting and they can’t edit what you say. The programme is almost inevitably running late, so last Saturday morning when I did an interview for Radio 4’s Today I remembered my media training and had prepared carefully to get my points over before they cut me off.

Was anyone right about the pre-election polls?

There has been much wailing and gnashing of blogs since the dismal performance of the pre-election polls last week. These had confidently and consistently predicted a rough tie in vote-share between Labour and Conservative, but when the votes were counted the Conservatives had a 6.5% lead.

Comparison of vote-share BBC Poll of polls on May 6th, and actual results on May 7th.

Sensationalist promotion by the World Cancer Research Fund

Today the Daily Telegraph featured the powerful headline "Just three alcoholic drinks a day can cause liver cancer, warns new study" , based on a press release from the World Cancer Research Fund headed “Three alcoholic drinks a day can cause liver cancer, new research finds”.

Misleading conclusions from alcohol protection study

The Daily Mail today declared that "Drinking is only good for you if you are a woman over 65", while the Times trumpeted that "Alcohol has no health benefits after all".

But these headlines are without serious foundation, and through no fault of the journalists.

How many hours of life did Obama lose in Delhi?

obama-delhi.png

President Barack Obama recently spent 3 days in Delhi, and it’s been claimed that during this period the air pollution knocked 6 hours off his life. So who was responsible for this number?

Luck and Cancer

I was on Radio 4 PM (starting at 37:09) and BBC News Channel yesterday discussing the study published in Science " Variation in cancer risk among tissues can be explained by the number of stem cell divisions ". This had been reported by much of the press as showing that “the majority of cancer cases are down to sheer bad luck”.

Sub-editing in the Times

A story in monday's Times had the following dramatic headline:
errors-screening-headline.jpg

Is prostitution really worth £5.7 billion a year?

The EU has demanded rapid payment of £1.7 billion from the UK because our economy has done better than predicted, and some of this is due to the prostitution market now being considered as part of our National Accounts and contributing an extra £5.3 billion to GDP at 2009 prices, which is 0.35% of GDP, half that of agriculture. But is this a reasonable estimate?

Why 'life expectancy' is a misleading summary of survival

It's well-known how misleading it can be to use average (mean) as a summary measure of income: the distribution is very skew, and a few very rich people can hopelessly distort the mean. So median (the value halfway along the distribution) income is generally used, and this might fairly be described as the income of an average person, rather than the average income.

Using expected frequencies when teaching probability

The July 2014 Mathematics Programmes of Study: Key Stage 4 (GCSE) specifies under Probability

{calculate and interpret conditional probabilities through representation using expected frequencies with two-way tables, tree diagrams and Venn diagrams}.

- the brackets and bold case means this comes under additional mathematical content to be taught to more highly attaining pupils.

Another tragic cluster - but how surprised should we be?

Sadly another passenger plane crashed yesterday - the third in 8 days, the Air Algerie flight on July 24th, the TransAsia flight in Taiwan on July 23rd, and Malaysian Airlines in Ukraine on July 17th. Does this mean that flying is becoming more dangerous and we should keep off planes? The following analysis may appear cold-hearted, but is not intended to diminish the impact of this tragic loss on the people and families involved.

Using metrics to assess research quality

The Higher Education Funding Council for England (HEFCE) is carrying out an independent review of the role of metrics in research assessment, and are encouraging views. I have submitted a (very personal) response, using HEFCE's suggested headings, which is given below in a minimally-edited version.

++++++++++++++++++++++++++++++

Numbers and the common-sense bypass

Yesterday the Sunday Times [paywall] covered a talk Anne Johnson and I had given at the Cheltenham Science Festival about the statistics of sex, and the article said

more people are having sex in their teens, roughly 30% before the age of 16.

A heuristic for sorting science stories in the news

Dominic Lawson's article in the Sunday Times today[paywall] quotes me as having the rather cynical heuristic: "the very fact that a piece of health research appears in the papers indicates that it is nonsense." I stand by this, but after a bit more consideration I would like to suggest a slightly more refined version for dealing with science stories in the news, particularly medical ones.

It's cherry-picking time: more poorly reported science being peddled to journalists

Yesterday the Daily Mail trumpeted “For every hour of screen time, the risk of family life being disrupted and children having poorer emotional wellbeing may be doubled”, while the Daily Telegraph said that "for every hour each day a child spent in front of a screen, the chance of becoming depressed, anxious or being bullied rose by up to 100 per cent”.

More deaths due to climate change? Or maybe not.

Coverage of a paper just published by Journal of Epidemiology and Community Health included dramatic headlines such as the Guardian's Heat-related deaths in the UK will rise 257% by 2050 because of climate change. But a closer look at the numbers in the paper paints a rather different picture.

How surprising was the cluster of cycle deaths in London?

More or Less recently featured Jody Aberdein talking about the cluster of 6 cycle deaths in London over a 2 week period.

The paper with the details of the analysis can, for a while, be freely obtained from Significance magazine.

PISA statistical methods - more detailed comments

In the Radio 4 documentary PISA - Global Education Tables Tested, broadcast on November 25th, a comment is made that the statistical issues are a bit complex to go into.

Complaint about the Press Complaints Commission

What a strange organisation the Press Complaints Commission (PCC) is. They say that a press article is inaccurate, but consider it reasonable that the inaccurate headline remains uncorrected.

Press Complaints Commission decide '13,000 needless deaths' story was inaccurate

I was of a number of complainants to the Press Complaints Commission about the Sunday Telegraph story headlined 13,000 died needlessly at 14 worst NHS trusts, as the Telegraph journalists had been explicitly told by the originator of the figures, Professor Brian Jarman, that this was an inappropriate interpretation.

New content for GCSE Maths announced

Following the consultation discussed previously on this blog, the Department for Education has announced the revised content for GCSE Mathematics.

Compared to the current content, the most notable changes are (a) separation of probability and statistics, (b) removal of the data-cycle, (c) increased material.

The proposed content for probability is as follows:

Probability and stats feature strongly in 'Core maths' proposals for 16-18 year olds

The government is pushing ahead with proposals for a maths qualification to be taken by 16-18 year-olds who got at least a grade C in Maths GCSE but are not doing maths A level.

September 19th is Huntrodds day!

When on holiday at Whitby we took this photo of this extraordinary memorial to Mr and Mrs Huntrodds.

Probability and stats in GCSE Maths

The current consultation on GCSE subject content and assessment objectives for Mathematics GCSE features major changes for probability and statistics.

I encourage everyone with an interest to respond (before 20th August): here is my personal take on the topic.

The proposals are as follows:

Fatality risk on Boris-bikes?

I was very saddened by the death on Friday of a Boris-bike rider in Whitechapel High Street, particularly as I am a frequent and enthusiastic user of the scheme. But as a statistician, I also immediately wondered how surprised I should be about the fact that this was the first fatality of the bikes.

Speed cameras, regression-to-the-mean, and the Daily Mail (again)

It was interesting to hear ‘regression-to-the-mean’ being discussed on the Today programme this morning, even if the quality of the debate wasn’t great. The issue was the effectiveness of speed cameras, which tend to get installed after a spate of accidents. Since bad luck does not last, accidents tend to fall after such a ‘blip’, and this fall is generally attributed to the speed camera, whereas it would have happened anyway: this is what is meant by ‘regression-to-the-mean’.

How can 2% become 20%?

The Daily Mail headline below is unequivocal – statins cause a 20% increase in muscle problems.

statin-muscles-mail.jpg

Court of Appeal bans Bayesian probability (and Sherlock Holmes)

..when you have eliminated the impossible, whatever remains, however improbable, must be the truth
(Sherlock Holmes in The Sign of the Four, ch. 6, 1890)

In a recent judgement the English Court of Appeal has not only rejected the Sherlock Holmes doctrine shown above, but also denied that probability can be used as an expression of uncertainty for events that have either happened or not.

What's more dangerous - the bute or the burger?

There is reasonable public outrage at possible criminal conspiracies to adulterate meat products with horsemeat, and additional concerns raised about the presence of the anti-inflammatory known as bute.

Squaring the square, in glass

Here is my latest stained glass effort, seen on a snowy day.

trinity-glass2-small.jpg

It is a 'square of squares', where all the constituent squares are of different sizes. Here are the dimensions -

sqsqbig.png

Alcohol in pregnancy and IQ of children

Some of the coverage of yesterday's story about drinking in pregnancy and IQ of children was not entirely accurate. The Times reported that 'women who drink even a couple of glasses of wine a week during pregnancy are risking a two-point drop in their child's IQ', and 'children whose mothers drank between 1 and 6 units a week - up to three large glasses of wine - had IQs about two points lower '(than mothers who did not drink).

More lessons from L'Aquila

The L’Aquila story gets even murkier.

The Continuing Tragedy of L’Aquila

As in ‘Boffins jailed for not predicting earthquake’, the 6-year sentences and massive fines handed out to the Italian seismologists have been largely portrayed by the media and commentators outside Italy as an attack on science, and the prosecution ridiculed as expecting the scientists to have been able to predict the earthquake.

Rats and GM

With others, I made some comments for the press about the recent paper (abstract, figures and tables freely available here) on cancer in rats fed GM maize and Monsanto's Roundup pesticide.
[ Full paper should also be available here].

Explaining 5-sigma for the Higgs: how well did they do?

Warning, this is for statistical pedants only.

Higgs: is it one-sided or two-sided?

Announcements about the Higgs Boson are invariably framed in terms of the number of sigmas, with 5-sigmas needed for a ‘discovery’. Media outlets helpfully explain what this means by translating 5-sigmas to a probability, which is almost invariably misreported as a probability of the hypothesis that it is all just statistical error e.g.

Drinking again

Alcohol can cause very serious problems, both for individuals, their families and society. But the Daily Mail’s story yesterday with the headline “Don't drink more than THREE glasses of wine a week: Oxford study claims slashing the official alcohol limit would save 4,500 lives a year” almost universally aroused derision among its many commenters.

Meat and dying

After all the recent coverage of the possible harms of red meat, I've done an article explaining how, if we believe the figures, eating quite a lot of extra red meat each week will take, on average, a year off our life.

Wiped Out

Appearing on Winter Wipeout today. Enough said.

insert alternate text

Looking deranged at the prospect of the Big Balls

Wrote an article for the Times, which appeared as this.

BBC website headline wrong shock horror

Bowel cancer screening 'does cut deaths', said the BBC News website today, in a report on a study using data from the NHS Bowel Cancer Screening Programme in England, published in the magnificently named journal Gut. Wow, I thought, that was quick, the programme has been going only since 2006 and didn't cover the whole country till 2010. Have they really found clear evidence of an effect on death rates already?

Why it’s important to be pedantic about sigmas and commas

The BBC reported last week that evidence for the Higgs Boson is “around the two-sigma level of certainty” and provides further explanation:

Particle physics has an accepted definition for a "discovery": a five-sigma level of certainty. The number of standard deviations, or sigmas, is a measure of how unlikely it is that an experimental result is simply down to chance rather than a real effect”

This is nice and clear, but it is also wrong, as we have pointed out before in a previous blog by Kevin McConway.

Are the Brits really fatter than other Europeans?

Lots of press reports in the last couple of days on how UK women are the fattest in Europe, for example in the Daily Mail and on the BBC News website. I'm still in Berlin, and it was in the papers here too. The tabloid-style Berliner Kurier went with the headline "Man, they are fat, man", while the N24 news service went with "British and Maltese are the fattest Europeans". But is it another dodgy league table?

The next Piccadilly line train is leaving from ....

Kings Cross Station now not only has a platform 9$\frac{3}{4}$, but also a platform 0. And for the numerically challenged, there are repeated announcements that 'customers are advised that Platform 0 is situated next to Platform 1'

kings-cross.JPG

I suppose the Underground platforms will now have to be given complex numbers.

The risk of queuing?

Got a short article in the Times today about the UK Border Agency relaxing its checks over the summer.

I wish I had included the following interesting information provided by the excellent Home Office Immigration Statistics April-June 2011. In 2010 there were around 100,000,000 admissions to the UK , and around 19,000 non-asylum individuals were refused entry. That's around 1 in 5000 admissions, about 35 plane-loads.

So someone should be able to estimate how many people were admitted who would otherwise have been refused entry - it may not be very many.

Another doubtful league table?

David Cameron has prominently commented on the recent performance tables concerning adoption in local authorities, in particular the proportion of children whose adoption placement occurs within 12 months. But are the local authorities really as different as they have been made out to be?

A probability paradox?

I recently tweeted a link to this problem drawn on a blackboard, which got a lot of retweets.

Multiple Choice: If you choose an answer to this question at random, what is the chance you will be correct? A) 25% B) 50% C) 60% D) 25%

This is a fun question whose paradoxical, self-referential nature quickly reveals itself – A) seems to be fine until one realizes the D) option is also 25%.

A Maserati for £1

After Dave and Angela Dawes won £101 million on the Euromillions lottery, Radio 5 Live asked me to comment on the different ways one could win a decent amount of money for £1. I chose £100,000, which will buy you a shiny new Maserati ( a Ferrari would be about double that). The recording of my interview is here, and here are the details of my calculations, which I hope are roughly correct.

Surgeons create Frankenstein numbers?

The BBC News website and Radio 4 news both led this morning on the Royal College of Surgeons' report on emergency surgery. The BBC web site states that
'A report by the college highlights figures that show that about 170,000 patients undergo emergency abdominal operations each year. Of these, 100,000 will develop complications and 25,000 of these patients will die.'

Divide and rule: getting rates in a mess

I've been a bit inactive in here for a few weeks, because I've temporarily moved to Berlin. But it turns out that one can find bad presentations of risk in the German media too, and here's one, pointed out to me by my new colleague Jan Multmeier. The topic is a serious one: suicide rates in German troops serving abroad, and the error involves dividing by the wrong thing when calculating rates.

The dangers of 'don't worry'

(appeared in the Times, 26th September 2011) - pdf here

Now that the rogue US satellite has crashed into the Pacific we can all come out from under our beds. The biggest bit of the satellite was about the weight of an adult gorilla, although not as soft, and travelled at 100 mph so it sounds rather ominous, but people only take up one 80,000th of the earth’s surface so it would be more than an unlucky day if anyone had been hit. 40 tons of debris got scattered over mainland USA after the Columbia shuttle disaster and nobody was injured, although NASA afterwards concluded there had been around a 1 in 4 chance of some casualties.

Get under the table?

The remnants of the Upper Atmosphere Research Satellite (UARS) are due to hit the earth later today and NASA have put up some details of their risk assessment. But this doesn't say where their '1 in 3200 chance of anyone being hit' comes from, and so can we get this figure from a back-of-an-envelope calculation?

Lottery league tables

The Daily Mail and other media sources have featured league tables for the 'luckiest parts of the country' based on the proportion of the population that have become millionaires by winning the lottery. Straight Statistics have done a nice demolition job on this absurd story, pointing out that any comparison should be based on the number of tickets sold, not the population.

Visualising uncertainty about the future

A great use of a 'spaghetti plot' of multiple model predictions for Hurricane Katia in this NBC news bulletin .

possible-hurricane_0.jpg

possible hurricane paths

Spotting a hoax using statistics

A report claiming that users of the Internet Explorer browser had lower IQs than users of other browsers has been revealed to be a hoax. I had been asked to comment on the report by BBC Technology and had got suspicious about the figures. The perpetrators of the hoax, which had received extensive coverage, have listed the reasons why they should have been detected, but did not include 'dubious statistics' in their list.

When does a single vote count?

1,362 Cambridge academics recently voted on ‘no confidence’ in the universities minister David Willetts, and this resulted in an exact draw with 681 voting each way: by the rules it meant the motion, or ‘Grace’, was not passed. A natural question to ask is: what was the chance of this happening?

Cats, cancer and confusion

If mobile phones don't cause brain tumours, what does? Well, according to stories today in the Daily Mail and the Daily Telegraph, it might be cats. Or at any rate a parasite called Toxoplasma gondii, one of whose hosts is the domestic cat. But don't go exiling your kitties yet; the admirable Ed Yong has explained in his blog that the study in question doesn't establish anything of the sort.

Mobile phones: where did the story go?

This Friday's xkcd comic was about mobile phones and cancer. Regular readers of UU will know that I've shown an interest in that subject before, here, here and here. The main point of the comic was good, but what's this "another huge study" on phones and cancer in the first frame of the comic, and why hadn't I heard about it?

World cup cephalopod fever

World cup fever is again gripping the globe - well, perhaps not so strongly as last time, but the Women's World Cup football finals are about to begin in Germany. And as the excitement builds, the aquarium chain that brought us Paul the "psychic" octopus is rising to the new challenge. Paul himself has ascended to the great aquarium in the sky, so the search is on for a worthy successor

Another ghastly graphic in the TImes

The Times has got another classic graphic today, which manages to be hideous, misleading and incomprehensible all at the same time - quite a feat. Why is this a pie-chart? Never mind, it all provides fine material for getting laughs when giving talks.


hideous, misleading and incomprehensible all at the same time

Spinning mobile phones

When it comes to causing cancer in humans, is using a mobile phone as risky as talcum powder, or as risky as coffee, or as risky as the notorious insecticide DDT? Actually we don't know, as I explained in my previous blog entry on last week's IARC announcement on mobile phones and brain cancer. That didn't stop the media comparing the risk of mobile phone use with all these things and more. But why did different newspapers make different comparisons?

Mobile phones: where's the uncertainty?

The media in the UK and many other countries have been full this week of stories about mobile phones and brain cancer. Some were really pretty scary - the Daily Express gave a SHOCK WARNING: MOBILE PHONES CAN GIVE YOU CANCER. But others were much more cautious. The BBC reported that a link between phones and cancer was "not clearly established" and that "the evidence was too weak to draw strong conclusions from." What's going on?

Statistician's ESP prediction comes true!

In our article on ESP and the significance of significance, I made a prediction on the controversy surrounding psychologist Daryl Bem's paper "Feeling the Future" - the one that claimed to find evidence for some forms of ESP (extra-sensory perception). "This one will run and run", I boldly prophesied. And so it came to pass.

Coffee and breast cancer

The media today are full of reports that women who drink lots of coffee might reduce their risk of developing one type of breast cancer. For instance, the BBC reported on it here, and the Daily Mail here. But is the evidence really there?

Heart disease screening: where did the uncertainty go?

The UK news media have reported quite extensively a newly published paper by Wald, Simmonds and Morris on screening for cardiovascular disease (CVD) - that is, disease of the heart and blood vessels (principally heart attacks and strokes). The paper concluded that screening should be based on the patient's age alone, and not on other risk factors for CVD. But I'm not going to examine the conclusion - I'm interested in the way the authors dealt with uncertainty.

Paul the Octopus: soon to hit the silver screen

Just up on Youtube is the trailer for the forthcoming feature film about Paul the 'Psychic' Octopus (RIP): not only does it feature DJS explaining the mathematics of Paul, but it includes Bayes theorem. And it is in Tentacular 2D!

Do mobile phones cause brain cancer?

The New York Times has published an excellent (well, I thought so) article called Do Cellphones Cause Brain Cancer?. What's particularly good about it is the clear but thorough way that it explains the problems of looking for causes of rare diseases, and describes the methods used for dealing with uncertainty in this challenging context.

Statistical significance, ESP and the law: what's all that about?

Statistical significance testing is one of the commonest formal ways of handling some kinds of uncertainty, but arguably it's one of the most misunderstood. We've posted a new article about statistical significance, in the context of some very controversial psychological experiments about extra-sensory perception (ESP).

Time to cut down on the booze?

The recent study on alcohol and cancer published in the British Medical Journal is a fine piece of epidemiology and attracted a lot of coverage of the estimate that 10% of male cancers and 3% of female cancers could be attributed to alcohol. But while it is useful as a description of what happens in populations, as usual when translated to an individual it stops looking so impressive.

A disastrous piece of risk communication?

Yesterday’s announcement that the Fukushima accident was now upgraded to a Level 7 was greeted with some consternation, since this is not only the same level as Chernobyl but as high as the scale can go – there is no Level 8. But is this scale really fit for its purpose?

Significance testing: a picture (well, cartoon) is worth 1000 words.

Statistical significance testing is a pretty tricky concept. We're planning to post an article on it soon, but until we get round to it, here's a link to something excellent on the topic from the xkcd Web comic. They're illustrating exactly what people misunderstand. Maybe we needn't bother with the article after all...

Screening for disease: why it's controversial

Screening for disease was in the news again in the UK last week. According to the BBC, a 20-year Swedish study of screening for prostate cancer showed that screening brought no benefit. (The actual study report didn't put it quite so baldly, but effectively did conclude there was no benefit.) This came just a couple of days after the Alzheimer's Disease Society asked that the NHS should offer checks for dementia to everyone (in the UK) when they reach the age of 75. Both these news items reported contrasting views on whether these screening checks are in fact advisable.

Spanish school books: can we believe what they say about health?

Most school textbooks contain messages about health. But there's no known evidence for about a quarter of the messages. At least, that's the position in Granada, Spain, according to a report in BMC Public Health.

Uncertainty in the media: a mixed picture on swine flu

BMC Public Health is one of those online, open access journals that are becoming more and more prominent in academic publishing. A couple of recent articles throw rather different lights on the communication of health messages to the public. One is pretty positive about how Australian television reported the 2009 swine flu epidemic. The other reports an analysis of school books in Spain, and I'll return to that in another blog entry.

Thinking, but not about uncertainty

Google seems to be doing pretty well everything these days. Their UK operation has just published the first issue of a new magazine, Think Quarterly, and it's all about data. It looks very pleasant, particularly if you read the version that emulates a print magazine. And there's some interesting content, including interviews with Hans Rosling and with Hal Varian, Google's Chief Economist who famously said in 2009 that "the sexy job in the next 10 years will be statisticians." But, strangely, the whole magazine says nothing explicit about uncertainty.

Poor forecasting: one approach to doing something about it

Philip Tetlock, an academic psychologist at the University of Pennsylvania, is famous in forecasting circles for his 2005 book Expert Political Judgment: How Good Is It? How Can We Know? He reported on a 20-year research project on expert forecasts in many different fields, and, to summarize crudely, found that most of the experts were pretty hopeless at forecasting. Now he's involved in another project to try to do something about this.

"Official": it does matter how risk statistics are presented

The respected and influential Cochrane Collaboration has just published a systematic review of research on different ways of presenting risks and reductions in risk in a health context. It won't come as a surprise to regular readers of this website that they concluded that some aspects of the presentation really do make a difference. But maybe there are a few surprises in their detailed findings.

Car insurance? How big are your feet?

Did an article in the Times [paywall] today on the forthcoming EU Court of Justice ruling on whether gender can be taken into account when setting insurance premiums. I think this is an important and interesting topic, but articles in the financial pages have been very dull and so tried to make this a bit lighter in tone. Text of article is here.

Odd odds

Ben McGarry pointed out this blog entry about an article published in Sexually Transmitted Infections Online that says some rather odd things.

Data: can we cope?

Are we all drowning in a deluge of data? Are our data tools and systems managing to keep up with all the numbers we're collecting all the time? A series of articles in the journal Science doesn't give an entirely positive view, at least in terms of what's going on in the scientific research community. But what does that have to do with uncertainty?

Daily Mail gets odds right shock

The Daily Mail and other papers carried the story about the Banwell family whose third child shares a birthday, February 5th, with two older siblings, and this time they got the odds right at 133,000 to 1!

Crime maps: how useful?

New online crime maps for England and Wales have just been published. They seem to show numbers of crimes for single streets. If you're in England or Wales, you'll probably have seen all the fuss about them in the media. But what do they actually tell us about the risks of crime?

The message in ley lines

Tom Scott has a marvellous web page, click here, that lets you check whether the place you live is on an ancient mystical energy highway. At least, it does if you live in England. If not, you can try one of the example postcodes he gives, or indeed the postcode of UU HQ here in Cambridge, CB3 0WB. Just don't forget to check the important warning that Tom gives after you've got your results.

Coincidence odds are wrong yet again

The Sun today features a story about a family who have had three children all born at 7.43 (two am and one pm). Heartwarming, but the quoted odds of 300,000,000 to one are sadly wrong.

Another priceless infographic from the Times ...

After their previous attempt at a Nightingale rose, here is another ghastly example from today's edition of the Times. Shouldn't someone tell them?


Perhaps Japan's acceptance rate looks more than twice the size of China's

Professeur Poisson still rules

We've previously shown that the number of homicides each day in London followed a Poisson distribution to a remarkable degree - this means that they essentially occur as a random process. Now the same analysis has been repeated by the Home Office in the crime statistics released today - and the Poisson fits very well.

Statistical relics

The bunting was out on Tuesday for the celebrations of the 100th anniversary of the first statistics department in the world at University College London! UCL was home to the great developments in statistics both before and after the department opened in 1911, with Karl Pearson as Professor of Applied Statistics, endowed by Francis Galton who had just died.

Can odds be awkward? I’d put money on that...

Assiduous readers of understandinguncertainty.org will know that we often refer to odds. Pretty well everyone will have heard of odds, and will at least know that they have something to do with how likely something is to happen. But beyond that, it can get trickier, as an entry in a blog about language has reminded us.

Stalin had a point

Got a Thunderer column in The Times today - giving local link rather than Times website due to their paywall. Links are provided to to the interesting post-mortems on the 2009 pandemic statistics.

Nice probability puzzle

For the last few weeks, Chris Maslanka's excellent maths puzzle column in the Guardian has been running variants on the following problem. Fred and Sam play a game in which the winner is the first to flip a head. They take it in turns, Fred starting. What's the chance that Fred wins? I have been asking this to 6th form audiences and the general response is 2/3 or 3/4, but nobody can say why. Here is the solution I have been using.

Mobile phones and behavioural problems

This article found an association between mobile phone use in pregnancy and behavioural problems in childhood, with an additional association with the child using a mobile phone before they were 7. I was not the only one reported as being sceptical, but the study is predictably getting a lot of coverage particularly in pregnancy advisory websites.

Do attractive people tend to have more daughters?

I got a commentary in the Times today (due to the Times paywall, this is a local link to the unedited article, rather than to the published version) about a study that estimated that people rated as 'unattractive' when they were 7 years old only had 44% chance of their first child being a girl. This effect seems utterly implausible.

Chance is a very fine thing

This month's Nrich has a fine collection of exercises on uncertainty, chance and coincidences, designed to be useful for primary schools to sixth forms. Have a look at the great lottery simulator, and try your hand at spinning 10 heads in a row like Derren Brown (there's a simulator if you get bored).

The money's in the bag

Got an article in the Times about the Walkers Crisps forecasting competition. Since then have won another £10. Shame the paywall means there is no point in linking to the online version.

A sad day for molluscs

We are sorry to hear that Paul the ‘psychic’ octopus has died. Who would have predicted it? Most people, in fact, since an octopus is only expected to live 2 years. Fortunately a documentary film team got to Paul before his demise and conducted in-depth interviews. They also filmed me doing an explanation of the maths behind Paul – this will probably be cut but at least we now have an article about him!

Making money from the rain

I have just won £10 in the Walker's Crisps Rainy Day promotion. Each packet of crisps has a code that allows you to choose a 2km x 2km square in the UK or Republic of Ireland in which you think it will rain in a couple of days time. I won after only three entries at a crisp cost of £1.20, which seems quite a good deal.

Hang out the flags!

The great day has arrived. The first UN World Statistics Day, that is, which naturally falls on 20.10.2010. The bunting is out, and statisticians everywhere will emerge from their data-mines, blinking through their pebble spectacles. They will throw off their drab grey suits and dance in the street, discard the row of pens in their top pocket and trim their unruly hair, their dull monotone will turn to song and they will stop staring at their shoes.

Not sure about the weather? Now's your chance to show it.

We are working with the Met Office on a project comparing alternative ways of presenting uncertainty about short-term weather forecasts, and have a 6-month internship available for a PhD student. See this link for details.

Strange how these "1 in 48,000,000" events keep on happening!

The Daily Mail has a story today about the Allali family whose third child was born on the same date as his two older siblings, claiming that "mathematical experts have revealed that the three siblings have beaten odds of 48 million to one". If these are the real odds, isn't a bit strange how often this story appears in the papers?

Alcohol, pregnancy and the precautionary principle

A recent study showed no evidence of an adverse effect of moderate consumption of alcohol during pregnancy and subsequent child development. But the Department of Health has commented "After assessing the available evidence, we cannot say with confidence that drinking during pregnancy is safe and will not harm your baby. Therefore, as a precautionary measure, our advice to pregnant women and women trying to conceive is to avoid alcohol."
Is this still a tenable position?

Handling uncertainty about climate change

The Inter-Academy Council (IAC) recently produced a report on the workings of the Intergovernmental Panel for Climate Change (IPCC) which got a lot of publicity, but almost no coverage was given to what the IAC said about the IPCC's way of handling uncertainty. It makes interesting reading.

Paul - the soothsaying cephalopod

Article in today's Times included below. I should have included the important observation that even if Paul's final two predictions are correct, it does not change my total belief that he is not psychic and the results are just chance. Essentially when a hypothesis has zero initial probability, no amount of surprising evidence will shift that belief. Oh dear, what a closed-minded person I am.

Risk-intelligence about children

This is an article that appeared in the Times on Friday July 2nd - sadly everyone now has to pay to access Times articles online.

Small but lethal risks - how dangerous is it to go into hospital?

We have an article on micromorts in Plus this month, featuring a simple but effective animation for comparing risks of different activities.

The risks of war and peace

Who is exposed to the greater lethal risk: a member of the UK forces serving in Afghanistan, or an average patient spending the night in an English hospital? Of course the question can’t be answered exactly: it all depends on who we mean and how we measure risk. But statistics can give us a ball-park figure that may be surprising.

Predicting the premier league results

Here is the spreadsheet showing the way in which my predictions were made. I hope it is comprehensible, at least for enthusiasts! I discussed this on the Today programme the day before the matches.

Calling all poor soothsayers: cash prizes for good forecasting

Do you reckon you have good statistical skills? Now's the chance to prove it in two forecasting competitions that are running this month, both of which feature the Eurovision Song Contest.

Sometimes statistical models really can predict what will happen

I have just put an article up on the science blog on The Times website about the recent 'breakthrough' in screening for colorectal cancer. Not only was this, for once, a real breakthrough, but it was almost exactly as predicted in a publication 17 years ago.

Can we say whether a drug would have enabled someone to live longer? Sadly not.

In the first televised election debate last Thursday, David Cameron stated that “I have a man in my constituency … who had kidney cancer who came to see me with seven others. Tragically, two of them have died because they couldn't get the drug Sutent that they wanted..”. How reasonable was it to claim that two would not have died had they had access to Sutent? Some statistical analysis can give us an insight.

Going out in a blaze of glory?

I got a mention on last Sunday’s Broadcasting House on Radio 4 as suggesting it was reasonable that older people should take more risks in their lives.

"Nothing ventured: balancing risks and benefits in the outdoors"

Do you think that kids are being over-protected and need more risk in their lives? If so, you may be surprised to find that the Chair of the Health and Safety Executive (HSE) and the Chief Executive of the Royal Society for the Prevention of Accidents (RoSPA) agree with you.

The English Outdoor Council has just released a fine report by Tim Gill,
"Nothing ventured: balancing risks and benefits in the outdoors" which "explodes the myths about safety on school visits and gives real reassurance to teachers"

Egg-gate: an update

I got an article in the Times about scientific uncertainty, and managed to squeeze in the 'six double-yolked eggs in a box' story as an example of 'unknown unknowns'. When the whole world was discussing the rarity of this event, it never even crossed my mind that I would walk into my local Cambridge Waitrose and buy, for £2.49, six double-egged yolked eggs in a box. But here's the proof!

Monkeys and Shakespeare

I was lucky enough to get included in the Horizon programme on Infinity last night, talking about the old monkey-Shakespeare issue. Of course most of my rambling contribution was (rightly) cut, so here’s a few background details for anyone interested.

The risks of Eggstasy

There has been extensive coverage of a box of 6 eggs found to be all double-yoked:an event that was given odds of a trillion to 1 against. This was based on the British Egg Information Service saying 0.1% ( 1 in 1000) eggs were double-yoked, and so getting six of these required these odds to be multiplied 6 times. In fact this gives 1 in 1,000,000,000,000,000,000, but which was reported as a trillion (now usually taken as 1,000,000,000,000).

The Daily Mail did a good demolition of this story, and it is a good example of what can go wrong when people try and work out chances.

Some risk announcements!

Some items to watch

Slightly embarrassing video

A video has gone on Youtube called Professor Risk as part of a series made for the Cambridge 800 years anniversary. To be honest it's a bit lightweight when it comes to risk, and all the subtle bits got cut. We filmed a whole lot more including my GP taking my blood, discussing statins and screening for prostate cancer. All on the cutting-room floor. Good point: Stephen Fry does the intro voiceover. Bad point: me in my jim-jams.

Can you rank hospitals like football teams?

Elsewhere on this site we talk about the difficulties in making reliable rankings of footbal teams, but at least people can agree that winning matches is a reasonable way to measure the quality of a team. Hospitals are different - even something 'obvious' such as mortality statistics may not be the best way to asses patient safety. This is an article that appeared in the Times on December 2nd, with suitable links added.

Ecstasy and equasy, heroin and hang-gliding

This appeared in the Times on November 3rd and is based on the excellent lecture that got David Nutt sacked as chair of the Advisory Council for the Misuse of Drugs (although he might still be in post if he had only added that it was delivered in his personal capacity). Nutt has suffered the consequences of repeatedly breaking the taboo of comparing the risks of the legal and wholesome (horse-riding) or long-established (alcohol and smoking), with the illegal and "impure" Ecstasy and cannabis.
The version below contains links to sources and a few comments and corrections.

What's the chance you've slept with a celebrity?

Brits three romps from celeb sex” headlined the Sun on Friday, adding that “boffins at Cambridge University have calculated every person in the UK is linked to a star through their sexual partners — with just three steps separating the average person from a steamy celeb romp”.

Some recent coverage

Random events tend to cluster, and just to illustrate this we've suddenly got a burst of coverage of our work:

Chance in football

To coincide with the kick off of the football Premier League 2009–2010 we have updated our articles on the role of chance in football, and we have updated our animation to include leagues from across Europe over the past twenty years.

Screening for disease and dishonesty

This is a rather late announcement of pages we have put up on the use of screening tests. Using lie detectors, breast cancer and HIV screening as examples, we show how an apparently accurate test, when applied to a group of people in which only a small proportion have the thing you are trying to detect, will generate many false positives.

Homo heuristicus

An event we are co-hosting with the Department of Social and Developmental Psychology "Homo heuristicus: Why biased minds make better inferences" by Professor Gerd Gigerenzer has once again got us wondering how we can make decisions in an ever uncertain world.

One game to go!

The final matches of the Premier League will be played this weekend. On One game to play! we've put an animation of the season so far, an analysis of whether Manchester United really is the best team, and some predictions for the weekend based on a statistical analysis of the season so far.

So how will Hull do against Man U on Sunday?

A Worrier's Guide to Risk

The Worrier’s Guide to Risk is intended to be a one-page check-list to help people make more sense of the seemingly unending series of stories on risk. This is a first draft, that has been produced in association with the Risk and Regulation Advisory Council, which is an independent advisory group which aims to improve the understanding of public risk and how best to respond to it in making and implementing policy.

Spinning risks

We've got a new animation showing all the ways we could think of for communicating a risk message. In particular, have a look what you can do when using absolute risks, expressed in natural frequencies, and using icons. The photos option is rather good, and we are planning to make it possible for anyone to put in their own examples, their own images, and embed the animation on their website.

We're nearly all at increased risk!!

Monday's headline in the Daily Telegraph: Nine in 10 people carry gene which increases chance of high blood pressure sounds shocking. Next thing they will be telling us that we are all going to die.

Does street lighting really reduce fatal road crashes by 2/3 ?

Cochrane Reviews are usually taken as the gold standard in putting the evidence together to check whether a treatment works. But a new Cochrane Review that examines how much the ‘treatment’ of putting in street lights prevents injuries and saves lives seems to suffer from some major flaws which could mean the claimed benefits from street lighting are greatly exaggerated.

Probability lessons may teach children how to weigh life’s odds and be winners

You might be interested to read this article in the Times on page 14 and an associated editorial on page 2. Also in the Times Online.

Survival back to 1845

We've added a version of our Survival animation that goes all the way back to 1845 in How long did we live?.
Can you spot the influence of the internal combustion engine in this data?

Florence Nightingale was a statistician!

Florence Nightingale is well known for her selfless nursing of the sick, and her pioneering reform of healthcare. Less well known is that she was also an accomplished statistician! We take a look at some of her finest work.

Nightingale's 'Coxcombs'

Through her work as a nurse in the Crimean War, Florence Nightingale was a pioneer in establishing the importance of sanitation in hospitals. She meticulously gathered data on relating death tolls in hospitals to cleanliness, and, because of her novel methods of communicating this data, she was also a pioneer in applied statistics. We explore the work of Nightingale, and in particular focus on her use of certain graphs which, following misreading of her work, are now commonly known as Nightingale's coxcombs.

Does it all add up?

Looks like another great talk for anyone interested in the public understanding of risk. Coming up on October 30th, by Professor Stephen Senn, as part of the Cambridge Festival of Ideas.

A Public Misunderstanding of Science Event

This should be entertaining and enlightening...

Ben Goldacre Poster 21st October 2008

"How the media promote the public misunderstanding of science" on Tuesday 21 October at 5.30pm in the Babbage Lecture Theatre, New Museums Site, Cambridge.

For further information on Ben's new book "Bad Science", please visit his website www.badscience.net

All are welcome to this free event, hope to see you there!

The Babbage lecture theatre is on the New Museums Site in Cambridge, which you can find here.

Time to hug a tree?

The Risk and Regulation Advisory Council (RRAC) is trying to stimulate public interest in a debate about how to manage the 'risk' posed by trees. Apparently around 6 people a year are killed by falling trees or branches, which does not seem a major problem, but nevertheless the British Standards Institute has produced a draft standard (BS 8516) for inspection of trees on a regular basis.

Risk in the media

One of our aims is to look at how the mass media portray risk stories, and what we might learn from that experience. The only way most people (including us) hear about potential risks is through the media, and understanding how they are reported may give us a better understanding of risk and uncertainty.

Day one

Hello, and welcome to the first blog entry from the Understanding Uncertainty team!

We hope you enjoy the site: it's only got a bit of content so far but there's lots more in the pipeline.

David S