The downside of discouraging pie charts
Two good charts can use better titles

Headless people invade London, chart claims

Some 10 days ago, Mike B. on Twitter forwarded me this chart from Time Out:

Timeout_londonpopulation_sm

Mike added: "Wow, decapitations in London have really gone up!"

A closer look at the chart reveals more problems.

The axis labels are in the wrong places. It appears that the second dot represents 1940 and the second-last dot represents 2020. There are 12 dots between those two labels, corresponding to three evenly-spaced labels. This works out to be  6.154 years between each dot, and 20.0 years between labels. The labels actually do not fall on top of the dots but between them! We have to conclude that the axis labels were independently applied onto the chart.

I found another chart of London's population growth from here.

Londonpopulationgrowth

Superimposing the two charts:

Redo_jc_timeout_londonpopulation_1

The lowest point seemed to be around 1990-ish in the second chart but in the Time Out chart, the reader most likely assumes it occurred around 2000.

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What else? The Time Out chart has no vertical axis, and therefore, the chart fails to deliver any data to the reader: how many people actually live in London? This style - chart with no vertical axis - has been made popular by Google (Google Trends, etc.). 

Further, one should differentiate between historical data and projections. It seems like everything on the right side that exists above the previous peak in 1940 is projected.

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Just for giggles, I made this:

Redo_jc_timeout_londonpopulation_2

 

 

Comments

Michael Schettler

Giraffe plot - I'll reapply for sure!

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