Pie Chart

Pie charts are used to illustrate proportions for categorical variables (nominal or ordinal data). An entire pie represents 100% of the measured variable. The sectors of a pie are proportional to the total number. Negative numbers and percentages over 100 are not presented in a pie chart. These charts are sometimes labeled as 100%, cake, circle, or percentage charts.

Figure 1 is a pie chart created with Microsoft PowerPoint that illustrates the percentage of time day cares devote to various activities during a 9-hour day.

The following are options that can be considered when creating a pie chart:

1.
Each pie sector has a color and/or pattern that distinguishes it from other pie sectors.
2.
The smallest pie sectors must be distinguishable.
3.
The largest pie sector starts at the 12 o'clock position.
4.
A legend is provided to the right of the pie chart.
5.
The percentages can be included either inside or outside each pie sector. They may be placed outside if the small sectors are not large enough to accommodate their size.

Figure 1 Percentage of Activities Pursued in Day Care