Pie Charts — Definition

Definition

A pie chart divides a circular whole into sectors whose angles represent category shares of a stated total. The full circle corresponds to 100 percent or 360 degrees. Pie-chart interpretation therefore depends on both the share and the total behind it.

A larger sector in one year's chart need not represent a larger absolute quantity than a smaller sector in another year's chart. The method is suitable for mutually exclusive parts of one whole, rather than unrelated measurements.

Comparing several pie charts requires particular care with changing totals, category definitions and whether the labels give angles, percentages or actual amounts.