National Traits and the Ecological Fallacy

This article caught my eye, headlined "Why criminals believe in heaven." [The Daily Mail's 'Science' and 'Health' pages are an unlimited resource for writing blog posts about bad statistics, but I promise to try not to only pick on them in future.]

The original paper is here (predictably the DM don't bother to link to it), and here is the university's press release which has been pretty slavishly copied to create the article.   The summary is, the researchers combined crime data from one source (the United Nations Office on Drugs and Crime), with survey data on people's attitudes to religion and other things (from World Values Surveys and European Value Surveys).  They found that the belief in heaven and hell is a strong predictor of crime rates at a country-wide level, whilst rates of particular religious beliefs were not.

Review: The Geek Manifesto

This week I've been reading Mark Henderson's book The Geek Manifesto: Why Science Matters, which discusses the role of science and its geeky proponents in public life. Henderson's principal thesis is that politicians and scientists have been wilfully ignorant of each other for too long, and that it is time for science, its methods, and its practitioners to take a more central place in politics and policy.  This includes statistics, of course, which is why it seemed relevant to the blog.

How should statistics be taught? Some thoughts.

Inspired by Timothy Gowers' recent post on how mathematics should be taught to non-mathematicians, I thought it might be prudent to ask how statistics should be taught.  If you need to be motivated as to how important teaching statistics is, watch Arthur Benjamin's short TED talk.

Newsflash: everyone being healthier reduces deaths

People like me often complain about the accuracy of scientific journalism, and the selective nature of the reports we see in the media; indeed, there's plenty to complain about.  However it's perfectly possible to misrepresent a story simply by choosing to place a particular spin upon it, usually one which makes the story seem more political than the original research.  It's easy to blame the newspapers for this, but often the problem is compounded by academic press releases, which are themselves designed to catch the eye of media outlets.

What is probability?

I haven't seen any particularly interesting (or unusually egregious) uses of statistics in the last few days, so it's time to have a more philosophical outing.  Of course, if you see anything in the news you think is worthy of a post, email me (evans [at] stats [dot] ox [dot] ac [dot] uk).

So to the title of the post - what is probability?  Probability can be viewed as just a mathematical construct, which we'll explore some other time, but even with the mathematical rules in place, there are various interpretations of what a probability actually is.  At school we usually think about rolling dice and flipping coins, so let's start there.  I flip a 50p coin: what's the probability that it comes up heads?  You'd probably [sorry] say it's 'evens', 'a half', 'fifty-fifty', or (as mathematicians generally prefer), '0.5'.

Fast food, dodgy infographics, implausible claims

The Daily Mail reported on Wednesday that US restaurant portion sizes had quadrupled(!) since the 1950s, a claim faithfully reproduced from the Center for Disease Control's (CDC) website.  The article comes complete with this infographic.

Now, it should be immediately obvious (if you remember your GCSE maths) that something is not quite right with this picture: the fountain soda looks truly enormous.  Taking the numbers in the diagram on faith for the moment (but see below), the volume of a cup has increased from 7 oz (200 ml) to 42 oz (1.25 l), a worrying factor of six increase.  In accordance with this, the 'NOW' cup on the diagram is 6 times taller than the 1950s cup.

Non-existent recidivism statistics wrongly reported

This article from the BBC News website caught my eye today, headlined "Reoffending rates reach record level".  It also says that 

Ministry of Justice officials say the figures show a "clear trend" of a rising re-offending rate.

The Independent makes some similar claims.  The phrase "re-offending rate" is simple enough: it's the proportion of people who, having been convicted of a crime, go on to commit another one within a year, or within five years, or whatever.  Right?