I have a great fondness for Scientific American. Even before starting medical school I would spend many hours reading Scientific American to get an overview of developments in science. The articles have always been of a high standard and easily engage the reader as well as getting the message out to a wide readership. However today I read this Scientific American Blog article about the work being done by the American Psychiatric Association to improve the reliability of Psychiatric diagnoses. The focus quickly changes to the author who tells us what he was thinking about things, how he got into an exchange with one of the presenters and how he walked out. Although the human element is always interesting, in science journalism it is expected that the science story will take precedence over behind-the-scenes soap operas. This is especially the case if the article has to be squeezed into a few paragraphs.
The author then manages to juggle the soap opera with a commentary about data presentation and again I have issue with this commentary. The author argues that the use of bar charts to display information about responses to a survey is ‘deceptive’ and suggests instead that pie charts should be used. I would argue to the contrary that with simple data, both methods of presentation are helpful. Here is an example and I will let the readers decide for themselves. Suppose we want to graph the following data
A=5 B=10 C=20 D=5 E=60
The data can be graphed with a pie chart or a bar chart as below.
As far as I can see both methods help me to quickly eyeball the data. In this example I cannot see how one diagram can be more ‘deceptive’ than another. The charts are simply representing the underlying data. So I challenge the assertion about the suitability of the bar chart based on my reading of the author’s article.
However after all of this, events further unfolded on Twitter. This time along with the author, two other twitterers who I hold in high regard, tweeted the piece uncritically to a combined audience of approximately 30,000 people. In my opinion, these issues detract from what should have been the main focus of the article – a discussion about the extensive scientific work done by the American Psychiatric Association to investigate and improve the reliability of Psychiatric diagnoses. In fairness, the author responded to one of my tweets and suggested he would clarify matters. I still hold Scientific American in the highest regards as i’m sure this article is just a blip for a periodical that has always achieved the highest standards of science journalism and brought science to popular culture.
The original article has been updated with the author agreeing on the point about the bar and pie charts and clarifying other points about the data presentation.
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