Archive for David Spiegelhalter

lunch with David [and Meursault]

Posted in pictures, Statistics, Travel, University life, Wines with tags , , , , , , , , , , , , , , on May 1, 2021 by xi'an

“My real beef, my real anger, is that hugely expensive programmes like test and trace did not have built in, right from the beginning, a capacity for experimental evaluation. They should have been running studies, different methodologies, different ways of tracing. As it is, we don’t know what benefit it’s had. It’s like rolling out vaccines without ever measuring whether they have an effect or not. For Heaven’s sake!”

journal of the [second] plague year [con’d]

Posted in Books, Kids, Mountains, pictures, Travel, University life with tags , , , , , , , , , , , , , , , , , , , , , , , , , on April 24, 2021 by xi'an

Read The Office of Gardens and Ponds (in French), by Didier Decoin [whom John l’Enfer I read more than forty years ago, with no lasting memories!], another random book found in the exchange section of our library!  While a pastiche of Japanese travel novels, the book is quite enjoyable and reminded me of our hike on the Kumano Kodō routes, two years ago. The tale takes place in 12th Century Japan and tells of the epic travel of a widow to the capital, Kyoto, carrying live carps for the gardens of the emperor. While some sections are somewhat encyclopedic on the culture of medieval Japan [and I thus wonder how Japanese readers have reacted to this pastiche], the scenario is rather subtle and the characters have depth, incl. the dead husband. The scene of the perfume competition is particularly well-imagined and worth reading on its own. I figure I will not bring the book back. (Warning: this book was voted a 2019 winner of the Bad Sex Award!). Also read Patti Smith’s Devotion, which was one of my Xmas presents. I had never read anything but Smith’s songs, since 1976 (!) with Horses, missing by little some of her concerts as on the week I was in Rimini… The book is quite light, and not only length-wise, made of two travel diaries in (to?) Paris and in (to?) Southern France, where she visits Camus’ house, and of a short story she writes on the train. While the diaries are mildly interesting, if a bit American-Tourist-in-Paris-cliché (like this insistence to find glamour in having breakfast at Café Flore!), the story comes as a disappointment, both for being unrealistic [in the negative sense] and for reproducing the old trope of the young orphan girl becoming the mistress of a much older man [to continue skating]. The connection with Estonia reminded me of Purge, by Sofi Oksanen, a powerful novel about the occupations of Estonia by Nazis and Soviet troups, an haunting novel of a different magnitude…

Made  soba noodles with the machine, resulting into shorte-than-life noodles, due to the high percentage of buckwheat flour in the dough, still quite enjoyable in a cold salad. Also cooked a roghan josh lamb shack, along with chapatis flavoured with radish leaves [no fire alarm this time] and a vegetable dahl whose recipe I found in Le Monde the same morn. Also took advantage of the few weeks with fresh and tender asparagus sold at the local market to make salads.

Watched a few episodes of Better than Us, Лучше (чем люди), a Russian science-fiction series set in a close future with humanoid robots replacing menial workers, until one rogue version turns uncontrollable, à la Blade Runner. There are appealing aspects to the story, besides the peep into a Russian series and the pleasure of listening to Russian, about the porous frontier between human and artificial intelligence. The scenario however quickly turns into a predictable loop and I eventually lost interest. Even faster did that happen with the Irregulars of Baker Street horror series, which I simply could not stand any further (and which connection with Holmes and Watson is most tenuous).

Having registered for a vaccination to the local pharmacy, I most got surprisingly called a few days later mid-afternoon to come at once for a shot of AstraZeneca, as they had a leftover dose. And a rising share of reluctant candidates for the vaccine!, despite David’s reassurances. I am unsure this shot was done early enough to get abroad for conferences or vacations in July, but it is one thing done anyway. With no side effect so far.

on Astra and clots

Posted in Books, Kids, pictures, Statistics with tags , , , , , , , , , , , , on March 16, 2021 by xi'an

A tribune this morning in The Guardian by David Spiegelhalter on having no evidence that the Oxford/AstraZeneca vaccine causes blood clots.

“It’s a common human tendency to attribute a causal effect between different events, even when there isn’t one present: we wash the car and the next day a bird relieves itself all over the bonnet. Typical.”

David sets the 30 throboembolic events among the 5 million people vaccinated with AstraZeneca in perpective of the expected 100 deep vein thromboses a week within such a population. Which coincides with the UK’s Medicines and Healthcare Products Regulatory Agency statement that the blood clots are in par with the expected numbers in the vaccinated population. (The part of the tribune about the yellow card reports, based on 10 million vaccinated people, reiterates the remark but may prove confusing to some!) As for hoping for a rational approach to the issue,  … we would need a different type of vaccine, far from being available! As demonstrated by the decision to temporarily stop vaccinating with this vaccine, causing sure additional deaths in the coming weeks.

“Will we ever be able to resist the urge to find causal relationships between different events? One way of doing this would be promoting the scientific method and ensuring everyone understands this basic principle. Testing a hypothesis helps us see which hunches or assumptions are correct and which aren’t. In this way, randomised trials have proved the effectiveness of some Covid treatments and saved vast numbers of lives, while also showing us that some overblown claims about treatments for Covid-19, such as hydroxychloroquine and convalescent plasma, were incorrect.”

Xs Xplain’d

Posted in Statistics with tags , , , , , , , , , , on January 31, 2021 by xi'an

tempDavid Spiegelhalter is starting a column in The Guardian about COVID-19, the first installment being about excess death statistics. Arguing rightly that it is “fairer to look at what has happened to the total number of deaths”, since this is an objective quantity (in countries with trustworthy death statistics). The discussion on how many of the excess deaths can be attributed to the pandemic is somewhat confusing, though, as little can be said with enough confidence, between the positive impact (flu deaths have plummeted, 30% less traffic deaths in France, &tc.) and the negative impact (stress, harsher economic or social conditions, &tc.) A worthy warning: the deficit in “other” deaths during the second wave is partly due to the extra deaths during the first wave, esp. for fragile and elderly persons.

politics coming [too close to] statistics [or the reverse]

Posted in Books, pictures, Statistics, University life with tags , , , , , , , , , , , on May 9, 2020 by xi'an

On 30 April, David Spiegelhalter wrote an opinion column in The Guardian, Coronavirus deaths: how does Britain compare with other countries?, where he pointed out the difficulty, even “for a bean-counting statistician to count deaths”, as the reported figures are undercounts, and stated that “many feel that excess deaths give a truer picture of the impact of an epidemic“. Which, on the side, I indeed believe is a more objective material, as also reported by INSEE and INED in France.

“…my cold, statistical approach is to wait until the end of the year, and the years after that, when we can count the excess deaths. Until then, this grim contest won’t produce any league tables we can rely on.” D. Spiegelhalter

My understanding of the tribune is that the quick accumulation of raw numbers, even for deaths, and their use in the comparison of procedures and countries is not helping in understanding the impacts of policies and actions-reactions from a week ago. Starting with the delays in reporting death certificates, as again illustrated by the ten day lag in the INSEE reports. And accounting for covariates such as population density, economic and health indicators. (The graph below for instance relies on deaths so far attributed to COVID-19 rather than on excess deaths, while these attributions depend on the country policy and its official statistics capacities.)

“Polite request to PM and others: please stop using my Guardian article to claim we cannot make any international comparisons yet. I refer only to detailed league tables—of course we should now use other countries to try and learn why our numbers are high.” D. Spiegelhalter

However, when on 6 May Boris Johnson used this Guardian article during prime minister’s questions in the UK Parliement, to defuse a question from the Labour leader, Keir Starmer, David Spiegelhalter reacted with the above tweet, which is indeed that even with poor and undercounted data the total number of cases is much worse than predicted by the earlier models and deadlier than in neighbouring countries. Anyway, three other fellow statisticians, Phil Brown, Jim Smith (Warwick), and Henry Wynn, also reacted to David’s tribune by complaining at the lack of statistical modelling behind it and the fatalistic message it carries, advocating for model based decision-making, which would be fine if the data was not so unreliable… or if the proposed models were equipped with uncertainty bumpers accounting for misspecification and erroneous data.