Tools - L - O

Tool 101: Line Chart

AKA

Line Graph

Classification

Analyzing/Trending (AT)

Tool description

A simple line chart is an ideal method for showing trends in quality, quantity, cost, customer satisfaction, and so on. It is often a first indication that some problem exists during the monitoring and tracking of quality performance data.

Typical application

• To monitor and track data over a period of time.

• To show a trendline analysis.

• To display change in quality performance.

• To identify shifts from predetermined averages.

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

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

links to other tools

before

• Frequency Distribution (FD)

• Checksheet

• Observation

• Focus Group

• Surveying

after

• Stratification

• Multivariable Chart

• Trend Analysis

• Pie Chart

• Pareto Chart

Notes and key points

• To enhance the interpretation of a line chart, a "goal for improvement" or a "standard" line should be drawn to verify actual performance to the desired goal or standard.

Step-by-step procedure

• STEP 1 Collect data from some source, such as a checksheet. See example Customer Complaints.

  

• STEP 2 Construct a line chart and apply the 3:4 ratio rule: The height of the Y axis must be 75 percent of the length of the X axis.

• STEP 3 Label the axes, plot and connect the data points, and draw the line as encoded in the legend. Date the line chart.

Example of tool application

Customer Complaints