Junk Charts: Black gold 22 Jul 2008

Great example of a junk chart from the Guardian...

As you can see, an oil barrel is used to illustrate the components that define the retail price of oil. What's the problem? Well, check out the colour-coding. If you ignore the lines that form the oil barrel and focus solely on colour for a moment, you'll notice that the green area is almost identical in size to the red. This indicates that the two areas represent roughly the same percentage of the total oil price. This isn't the case, however. The figures to the right of the diagram reveal that the green area is supposed to represent 8.9% of the oil price, while the red area is supposed to represent 32.4% of the price - thus the red area should look roughly 3.6 times larger than the green. D'oh!

If only they had coloured the top of the cylinder (i.e. the lid) grey...