Tag Archives: HBR

On spurious correlations

When this came through my inbox this morning, all I could think was, “How have I never found this blog before?” Harvard Business Review has a new article – “Beware Spurious Correlations” – that features the absurd (like an example of how iPhone sales correlates visually with U.S. deaths from falling down stairs) and the serious implications of what that means for those visualizing data and inferring unproven causal relationships.

The teaser from HBR:

“We all know the truism “Correlation doesn’t imply causation,” but when we see lines sloping together, bars rising together, or points on a scatterplot clustering, the data practically begs us to assign a reason. We want to believe one exists.

Statistically we can’t make that leap, however. Charts that show a close correlation are often relying on a visual parlor trick to imply a relationship. Tyler Vigen, a JD student at Harvard Law School and the author of Spurious Correlations, has made sport of this on his website, which charts farcical correlations—for example, between U.S. per capita margarine consumption and the divorce rate in Maine.”

Read the article for the full explanation, but all to say, be thoughtful about how you visualize your data – don’t fall prey to misleading with charts and graphs.

Using a simple matrix to visualize country correlations

Harvard Business Review recently posted a visualization from an article about Contextual Intelligence, focused on the cross-cultural relevance of learning about different business practices.  While not health or explicitly development related,  their approach to visualizing connections between countries was elegant in it’s simplicity and worth sharing.

HBRMatrix

 

The visualization uses what has become an increasingly common scrolling approach (also seen in Tableau Story Points, the Wall Street Journal, and other design tools and publications), which helps to visualize a story by guiding the reader’s eye as s/he clicks through a series of graphs or charts.

What we liked about this particular example is the smart use of color, simplifying the initial matrix into visualizations only highlighting particular country connections).

HBRMatrix2

Take a look at the full visualization on the HBR blog—does this example make you think in new ways about how to use a matrix to illustrate a data story?

Strategic color choice to improve your graphs

Take a look at these two graphs of fruit sales:

A recently published study from Harvard Business Review looked at how the color choices impacted how people analyzed the data.  They pose the following questions about the data in the charts:

Which fruit had higher sales: blueberries or tangerines? How about peaches versus apples? Which chart do you find easier to read? Continue reading Strategic color choice to improve your graphs