Paul Taylor

Paul Taylor is professor of health informatics at UCL.

From The Blog
12 February 2021

As chest X-rays of Covid-19 patients began to be published in radiology journals, AI researchers put together an online database of the images and started experimenting with algorithms that could distinguish between them and other X-rays. Early results were astonishingly successful, but disappointment soon followed. The algorithms were responding not to signs of the disease, but to minor technical differences between the two sets of images, which were sourced from different hospitals: such things as the way the images were labelled, or how the patient was positioned in the scanner. It’s a common problem in AI. We often refer to ‘deep’ machine learning because we think of the calculations as being organised in layers and we now use many more layers than we used to, but what is learned is nevertheless superficial.

When​ I first studied artificial intelligence in the 1980s, my lecturers assumed that the most important property of intelligence was the ability to reason, and that to program a computer to perform intelligently you would have to enable it to apply logic to large bodies of facts. Logic is used to make inferences. If you have a general rule, such as ‘All men are mortal,’ and a...

Short Cuts: Ofqual and the Algorithm

Paul Taylor, 10 September 2020

As​ the UK moved into lockdown in March, Gavin Williamson, the education secretary, announced that this summer’s GCSE and A level exams would be cancelled. The exams regulator, Ofqual, was instructed to put in place an alternative system to allow students to move on to further study or employment while ensuring that they would be neither advantaged nor disadvantaged compared to those...

The argument between mitigation and suppression now seems to have been settled in favour of the latter. But when the lockdown ends, a calculation will still have to be made about the relative merits of unappealing alternatives. The poor public understanding of mortality rates won’t make this any easier. The situation isn’t helped by the fact that two very different numbers are reported: daily totals of confirmed cases who died in hospital and weekly totals of later registrations, including many, perhaps 18 per cent of the total, who died outside hospital. The reporting of the epidemic also fails to place deaths from the virus in the context of normal mortality rates. When you read the daily updates of the number of hospital deaths, you aren’t reminded that last year, in England, an average of 1360 people died every day, a total of 496,354 for the year. In London right now, the death rate is way above normal, but for the UK as a whole the number of deaths in March 2020 was lower than in the same month last year. 

From The Blog
29 April 2020

The hope is that almost all of us will download the app, that we will be diligent about using it if we develop symptoms, that the detection of identifiers will be reliable, that the subsequent risk calculation will be more or less accurate, and that we will, by and large, self-isolate if the app tells us to. Crucially, the strategy also requires easy access to tests so people can be rapidly alerted if a contact who had symptoms turns out not to have had the disease.

Whose Property? Big Medical Data

Paul Taylor, 8 February 2018

Patients​ often complain that their GP spends more time typing and looking at a computer screen than listening to them. This isn’t really new: doctors have kept records of their encounters with patients since the time of Hippocrates. But changes in record-keeping practices have both reflected and enabled the development of modern scientific medicine, which is less concerned with...

The conventional way of writing, say, a chess program has been to identify and encode the principles underpinning sound play. That isn’t the way DeepMind’s software works. DQN doesn’t know how to repel an invasion. It doesn’t know that the electronic signals it is processing depict aliens. DeepMind searches the game data for correlations, which it interprets as significant features.

Breast Cancer Screening

Paul Taylor, 5 June 2014

In December 2013 the House of Commons Select Committee on Science and Technology announced an inquiry into the efficacy of screening for cancer. ‘The NHS spends a significant amount of money on health screening,’ Andrew Miller, the chair of the committee, said, ‘and it is important that this is underpinned by good scientific evidence.’ But the awkward truth is that much of the evidence is contested. The argument over breast cancer screening has been going on for decades, often bad-temperedly, and concerns not just the efficacy of the screening itself but its potential to do harm as well as good.

Rigging the Death Rate

Paul Taylor, 11 April 2013

The publication in February of the Francis Report into the failings of the Mid-Staffordshire NHS Foundation Trust was the worst of the many recent bad news stories about the NHS, its significance underscored by the fact that David Cameron felt it necessary to present the report to the House of the Commons himself, rather than leave it to the secretary of state for health. The public inquiry was set up in 2010 by the then secretary of state, Andrew Lansley, to investigate further the findings of a previous inquiry, commissioned by the Labour health minister.

From The Blog
7 May 2018

Jeremy Hunt announced last Wednesday that as many as 270 women may have died because an error in a computer algorithm prevented 450,000 women being invited for routine breast cancer screening appointments. Stories about IT glitches will be increasingly common as artificial intelligence enables more and more healthcare to be automated. As things stand, people are still better than computers at detecting early signs of cancer on mammograms, and the neural networks currently being designed to analyse the images are intended for use as an aid rather than a replacement for human decision making. The hope is to engineer systems that combine the different strengths of humans and computers, with outcomes that neither is capable of independently. The sad reality is that we seem to end up with systems that combine an all-too-human capacity for error with a computer’s blunt force, and so wreak havoc at an inhuman scale.

From The Blog
15 May 2017

There are no good news stories about computers and the NHS. The reporting of Friday’s malware attack may, however, be usefully different from the typical bad news story, in which hubristic politicians or nameless bureaucrats waste millions, if not billions, of public funds on projects which go over budget, fail to deliver, prove to be unusable or collapse under pressure. In this instance it seems that, for once, inaction and underinvestment have led to something sufficiently focused to be newsworthy, showing that there can be a political as well as a human cost to doing nothing.

From The Blog
10 February 2016

‘Around 6000 people lose their lives every year because we do not have a proper seven-day service in hospitals,’ Jeremy Hunt said on 16 July 2015. ‘You are 15 per cent more likely to die if you are admitted on a Sunday compared to being admitted on a Wednesday.’ A Department of Health statement later clarified that the figures came from an analysis ‘soon to be published in the BMJ’. Nick Freemantle, a professor of epidemiology at UCL, had been invited by Bruce Keogh, the chief medical officer, to update a 2012 analysis of hospital data, apparently on the suggestion of Simon Stevens, the new chief executive of NHS England. The resulting paper wasn’t accepted by the BMJ until 29 July, after Hunt’s speech. When it appeared in September, it contained no reference to the 6000 figure.

From The Blog
2 June 2015

London’s two velodromes were built in the 19th and 21st centuries. The indoor track at the Lee Valley Velodrome, one of the fastest in the world, is housed in a beautiful stadium built at cost of £94 million. Its distinctive roof, a hyperbolic paraboloid clad in 5000m2 of custom-cut Western red cedar, is a prominent landmark at the edge of the 2012 Olympic park. The open-air track at Herne Hill is completely hidden in a South London suburb.

From The Blog
27 March 2014

At the centre of Monday night’s Panorama programme on fraud in the NHS was an interview with Jim Gee, an expert on the financial cost of healthcare fraud. Gee showed the presenter a newly published report, of which he was the first author, and talked about its findings. He turned to a key page and the camera picked out a bar chart as the two discussed some of the figures it contained. The report was also given wide coverage in the print media this week. Stories were run in all the broadsheets and across the tabloids with many local papers picking up the story and giving it a local spin. The figure, highlighted in Panorama, that most journalists seized on was the estimate that fraud was costing the NHS around £7 billion a year, enough – the Express pointed out – to pay for 250,000 nurses.

From The Blog
21 January 2014

According to the front page of yesterday’s Guardian, the NHS is to start selling our confidential medical records. Every doctor has a duty to keep patient-identifiable data secure, and only share it as far as is in the patient’s immediate best interests. At the same time, in order to run healthcare organisations or to carry out medical research, it is necessary to compile statistics about diseases and treatments. It therefore makes sense for some information collected in the course of caring for patients to be made more widely available – shared with managers, bureaucrats and researchers – but only if it is anonymised.

From The Blog
17 October 2012

When Alan Sokal tricked Social Text into publishing a nonsensical parody of postmodernist criticism, he thought the journal’s failure to spot that the article was a hoax revealed a shocking lack of intellectual rigour. John Sturrock, writing about it in the LRB, noted that Social Text exists in a different realm of discourse from Nature and that Sokal’s contribution, for all its faults, was a ‘jauntily expressed’ piece of ‘extreme provocation’, and as Sokal knew, the kind of thing that Social Text existed to promote. Well yes, but, as legions of letter writers responded, don’t things you publish sort of have to make sense? Last month That’s Mathematics! reported another landmark event in the history of academic publishing.

From The Blog
5 May 2011

Perhaps David Cameron was worried about the dissonance between his pre-election pledge to put an end to top-down reorganisations of the NHS and the post-election labelling of his government’s proposed changes as the biggest reorganisation that the service has ever seen. Perhaps Nick Clegg was unhappy that two months after the key Lib Dem health policy – elected representatives on Primary Care Trusts – was written into the coalition agreement, he was being asked to support the abolition of the PCTs. Who knows, but they must have been pretty unhappy with the politics of NHS reform to have ordered a pause in the progress of the bill to allow for a ‘listening exercise’.

From The Blog
16 December 2009

The four most ‘informative’ words in Moby-Dick, statistically speaking, are ‘I’, ‘whale’, ‘you’ and ‘Ahab’. Marcello Montemurro and Damian Zanette worked this out by comparing the text of Moby-Dick to all the possible alternatives obtainable by shuffling Melville’s words into random sequences. These are not the four words that are used most often, or that carry the most ‘information’ in the everyday sense of the term, but the words whose positioning in the original, meaningful text differs most from the way they would be scattered in all other permutations. The ‘information’ here is of the mathematical, measurable kind: ‘most informative’ means ‘least randomly distributed’. It may seem a slightly odd way to try to quantify semantic content, as though when Melville wrote Moby-Dick, it wasn’t so much a matter of finding the right words, as of putting them down in the right order.



6 June 2019

Ben Jackson wonders what impact AlphaZero, a computer program capable of teaching itself to play games at a superhuman level, will have beyond chess (LRB, 6 June). How many ‘real-world situations’, Jackson asks, ‘can be productively reduced to a process of optimisation, with a unitary goal and a predefined set of rules’? Deepmind, the artificial intelligence research company...

Go Ogle

26 January 2006

In a future development that Tim Berners-Lee calls the Semantic Web, search engines will reason about a page’s contents, rather than relying on bibliometrics as they do at present. Currently, web pages are marked up with html tags that tell a browser how to display them. Tags in the Semantic Web will indicate what a site is about and be drawn from ‘ontologies’, specifications of the...
David Runciman’s account of the injection of choice into the NHS doesn’t mention ‘Choose and Book’, a project intended to transform the process of allocating outpatient appointments. Instead of being put on a waiting list and subsequently given a date for an appointment, patients will be able to book appointments with the help of their GP, through a call centre or via the web....

What about Gödel?

22 July 2004

Most readers who enjoyed A.W. Moore's brisk demonstration that an arithmetisation of meta-mathematics produces provably unprovable propositions (LRB, 22 July) will have heard of Kurt Gödel, and some will recognise this as the work for which Gödel is famous. Without any mention of Gödel's theorem, however, Moore's article seems incomplete.


6 November 2003

Since it is impossible to say how many people should go to university, the Government's target of 50 per cent of all those between 18 and 30 must have been selected for its electoral appeal, Stefan Collini tells us (LRB, 6 November). His tone is accusatory, as if this were a cynical ploy, but given the general tone of its other policies, that the Government should base its appeal to the electorate...
Thomas Laqueur writes (LRB, 29 July) that a medical textbook becomes obsolete within five years. In fact the information in a textbook may be out of date long before the book is published. The routine use of streptokinase in myocardial infarction, for example, began to be advised in textbooks in 1987, 13 years after an analysis of the published clinical trials would have revealed clear and compelling...

Europe’s War

29 April 1999

John Sturrock (LRB, 29 April) might be interested to learn that one anagram of ‘London Review of Books’ is ‘no wind of rebel Kosovo’.
Peter Campbell’s piece on medical imaging (LRB, 31 July) expressed a wish to know more about the mathematics of tomography. The problem is to reconstruct an image of a slice through a body from a set of readings, known as projections, taken as an X-ray source and detector are routed in a circle around the slice. If we know what is in a body we can calculate what will happen to an X-ray that passes...


20 March 1997

John Lanchester (LRB, 20 March) suggests that doctors believe we drink twice as much as we let on. The evidence supports the doctors: according to an article published in the journal Addiction in 1995, no counterfeit production or illegal importation of alcohol exists on the island of Spitzbergen, so a comparison of figures for the sale of alcohol with the islanders’ self-reported consumption...


3 August 1995

The excellent service you provide in pointing out your correspondents’ errors slipped up last week when you allowed Roger Pebody (Letters, 7 September) to write that since gay men are more readily found in London than Northumberland, geographically random sampling was inappropriate to measure the frequency of homosexuality. It is precisely because researchers are alert to systematic biases that...
John Allen Paulos (LRB, 11 March), explains how psychologists can devise situations which lead unsuspecting subjects to make supposedly irrational choices. This must be entertaining for lovers of practical jokes, but it is not clear what it reveals about human rationality. We are told that, when asked whether ‘r’ occurs more often as the first or the third letter of a word, people answer...

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