Bar charts and pie charts highlight different aspects of the data

For quantities that are not partitions of some total (e.g. life expectancies or death rates in several countries), only bar charts should be used.

For data that do form a partition of a total (e.g. a frequency table), both a bar chart and a pie chart are valid representations of the data. However, although both are visual representations of the same values, they highlight different features of the data.

Pie charts are particularly useful if the categories are ordered in some meaningful way.

World rice production

The table below shows world rice production (in thousand tonnes) in 1996. The seven major rice-producing countries are separately shown.

Country Rice production
(million tonnes)
Percentage
China
India
Indonesia
Bangladesh
Vietnam
Thailand
Other Asian
Outside Asia
197.1
120.8
51.1
26.5
26.4
21.8
56.2
67.0
34.8
21.3
9.0
4.7
4.7
3.8
9.9
11.8
Total
566.9
100.0

A pie chart and a bar chart are shown below.

Rice production was similar in Bangladesh, Vietnam and Thailand and they are very hard to distinguish in the pie chart. (Click on segments to read off the exact proportions of world production.) In the bar chart, it is clearer that production in Thailand is lower than in Bangladesh and Vietnam. The difference between China and India is even clearer in the bar chart.

On the other hand, the pie chart shows that just over half of the world's rice was produced in China and India since these categories span about half of the circle. A further quarter was produced in the next four countries (Indonesia, Bangladesh, Vietnam and Thailand) since their combined 'slice' is a further quarter of the circle. This information is not immediately apparent in the bar chart. Drag over adjacent categories with the mouse to read off the proportions in these groups. (Push the mouse button down over one segment and move the mouse with the button kept down over other segments.)