Bar charts and pie charts highlight different aspects of the data
Although a bar chart and a pie chart are visual representations of the same values (the proportions in the categories), they highlight different features of these proportions.
Bar charts provide better comparisons of the individual proportions, whereas pie charts allow us to assess the proportions in two or more adjacent categories.
Kestrel deaths
The following frequency table shows the causes of death of kestrels (a bird of prey) in Britain between 1963 and 1997. (Carcasses were sent to the researchers in response to advertisements in bird-watching magazines and journals and the cause of death was found from information sent by the finder and examination of the carcass.)
Cause of death | Frequency | Percentage | |||
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Total | 1473 |
A pie chart and a bar chart are shown below.
The bar chart shows that the proportion who died from road accidents was slightly lower than the proportion who died from other traumas. This is less obvious from the pie chart. Click on the categories to read off the exact proportions.
On the other hand, the pie chart shows that about half of the kestrels died from natural causes (disease, starvation and some of the 'unknowns') since these categories span about half of the circle. This information is not immediately apparent in the bar chart. Drag over adjacent categories to read off the proportion of deaths in these groups.