Type D charts

A twitter follower sent the following chart:

It's odd to place the focus on China when the U.S. line is much higher, and the growth in spending in the last few years in the U.S. is much higher than the growth rate in China.

In the Trifecta Checkup, this chart is Type D (link): the data are at odds with the message of the chart. The intended message likely is China is building up its military in an alarming way. This dataset does not support such a conclusion.

The visual design of the chart can't be faulted though. It's clean, and restrained. It even places line labels at the end of each line. Also, the topic of the chart - the arms race - is unambiguous.

One fix is to change the message to bring it in line with the data. If the question being addressed is which country spends the most on the military, or which country has been raising spending at the fastest rate, then the above chart is appropriate.

If the question is about spending in China, then a different measure such as average annual spending increase may work.

Neither solution requires changing the visual form. That's why data visualization excellence is more than just selecting the right chart form.

Comments

[Jeff]

I think part of the issue is that the graph plots military expenditure per capita. China's population is more than 4 times that of the US; if the Y axis represented total spending, the China trend would be steeper. And, to be fair to the headline writer, it does appear to be rising steadily.

Whether a per-capita comparison of military spending is a useful one depends on the point they're trying to make.

[Richard Krablin]

The chart features per capita spending. Given the difference in population, I do not see the real meaning of that or the relevance. Which military is increasing the most? Why not just state such a number? What about the absolute amount spent? The annual data seems to add little, except to say the US increased spending under Trump.