kevin's blog

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.

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).

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.

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