How to read numbers
(25 March 2021)
To answer some of life’s questions, we often rely on numbers. How we hear about these numbers though, is often through the media. The problem with this is that the way the media uses numbers isn’t particularly reliable.
A lot of the time, numbers are misunderstood, misrepresented, or misused.
This is all insight from a new book and accompanying campaign, ‘How to Read Numbers’ by Assistant Professor in Economics Dr David Chivers and cousin Tom Chivers, a journalist at UnHerd.
Worrying and scary percentages
An example they use in their new book is that in 2018, The Telegraph published an article informing readers that children born to men over the age of 45 were 18% more likely to have seizures.
This can sound very alarming and worrying. Some people may even read this and think that children born to older fathers have an 18% chance of developing seizures, which is not true.
The question that needs to be asked is, 18% more than what? It is much more informative to reformulate the risk in absolute terms, rather than relative.
Dr David Chivers and Tom Chivers then explain that the risk of a child having seizures is 0.024%. If the father is in his 50s, the risk is now 0.028%. The absolute risk increase is 0.004 percentage points. They comment: “This sounds much less scary, and a lot more informative to the readers: we now have a better grasp of the actual risk involved.”
A practical guide
Each chapter of the new book, How to Read Numbers: A Guide to Statistics in the News, takes a real-life news story and uses it to highlight a particular concept or idea. Other examples are topics such as whether swearing makes you stronger or if drinking soft drinks makes you violent.
The authors said: “We present a statistical style guide and have started a campaign to try and get journalists to follow it in the vain hope that it will make the world a better place.
Although, the question we should be asking is: how do we actually know if we have made a difference?”