Tool 133: Pie Chart

AKA

Circle Chart, Distribution Ratio, Area Graph

Classification

Analyzing/Trending (AT)

Tool description

A pie chart presents data very efficiently and is useful for general comparison of parts or ratios. The circular graph illustrates the relationship of the various parts, each part representing a percentage of the whole.

Typical application

• To display the relative contributions of different subcategories of data.

• To identify ratios or proportions.

• To establish priorities for action.

• To focus on problems or causes.

Problem-solving phase

→	Select and define problem or opportunity
→	Identify and analyze causes or potential change
	Develop and plan possible solutions or change
→	Implement and evaluate solution or change
→	Measure and report solution or change results
	Recognize and reward team efforts

Typically used by

1	Research/statistics
	Creativity/innovation
	Engineering
2	Project management
	Manufacturing
3	Marketing/sales
	Administration/documentation
4	Servicing/support
5	Customer/quality metrics
	Change management

links to other tools

before

• Frequency Distribution (FD)

• Checksheet

• Observation

• Surveying

• Focus Group

after

• Two-directional Bar Chart

• Demographic Analysis

• Cost-Benefit Analysis

• Pareto Chart

• Presentation

Notes and key points

• The parts of a pie chart must total 100 percent. Group small percentage items and label them "other." Draw no more than 10 parts, using alternate fill patterns or colors.

Step-by-step procedure

• STEP 1 Collect the data and verify accuracy. See example Cost of Quality Budget.

• STEP 2 Identify data categories and determine percentage for each.

• STEP 3 Draw circle for the pie chart; include a small circle in the center to represent the whole.

• STEP 4 Label each part (category) and indicate its percentage.

• STEP 5 Use different shading, fill patterns, or color for parts. Date the pie chart.

Example of tool application