Thursday 22 May 2014

Bad Infographic of the Day

Whilst browsing the MoneySavingExpert website over lunch today I came across this good example of a bad infographic:


It appears on the page about cheaper fuel and is intended to illustrate how the cost of a typical litre of unleaded petrol breaks down.

There are two problems with the above graph.  Firstly, most of the percentages shown in brackets are wrong.  For example, a very quick and simple bit of mental arithmetic will tell you that 5p is not 6% of £1.30, but less than 4%.  However, this is not the main problem with the graph.  The main problem is that the areas of the graph are all wrong; it significantly under-represents the portion of the petrol price attributable to fuel duty and to the manufacturer, slightly over-represents VAT and massively over-represents the retailers cut.

I've produced a corrected version of the infographic, which is shown below.  See if you can spot the difference:


MoneySavingExpert claims the data for the infographic comes from PetrolPrices.com; I can't find the infographic there, so I'm guessing that's MoneySavingExpert's own work.  There are a couple of graphics on this page that aren't any better, although they just appear to show the cost breakdown numerically, with the larger numbers written in a larger font to give them more prominence - they aren't quite as potentially misleading.

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