Six Sigma Tool Navigator: The Master Guide for Teams

2017-07-07 02:10:07

AKA

Scatter Analysis, Scatterplot

Classification

Analyzing/Trending (AT)

Tool description

The scatter diagram is an analysis tool that plots related pairs of variables (factors) to display a pattern of relationship or correlation. This tool is extremely useful in detecting possible causes of a problem, the strength of the relationship, and how the change of one variable can affect the other.

Typical application

To determine if a relationship exists between two sets of data.

To demonstrate that a change in one activity or condition will affect the other.

To verify a possible cause to an observed effect.

To illustrate process improvement.

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
	Project management
3	Manufacturing
5	Marketing/sales
	Administration/documentation
4	Servicing/support
2	Customer/quality metrics
6	Change management

links to other tools

before

Checksheet

Data Collection Strategy

Events Log

Defect Map

Cause and Effect Diagram (CED)

after

Presentation

Information Needs Analysis

Trend Analysis

Potential Problem Analysis (PPA)

Cost of Quality

Notes and key points

Scatter patterns of correlation:

Step-by-step procedure

STEP 1 Select two sets of data (variables) for plotting. See example Errors Made in Document Processing.

STEP 2 Sort or rank the data pairs from low to high for both data sets.

STEP 3 Construct a diagram and scale both axes in accordance with observed data pairs, from low numbers to high numbers of occurrence. For example, the X axis reflects a scale from 0 to 140 documents processed per day, the Y axis shows a scale from 0 to 25 errors made per day.

STEP 4 Plot related data pairs on the grid—the diagram. Be careful in measuring the exact location of the intersecting point.

STEP 5 Label and date the scatter diagram.