4S

Use a 4S to identify potential causes of a problem using the following categories: Suppliers, Systems, Surroundings, and Skills.

Watch this video to learn more:

Answers the questions:

What are the potential causes for a particular type of defect?
What are the process inputs that contribute to variation in the process output?

When to Use	Purpose
Pre-project	Assist in project identification by linking potential causes to defects.
Start of project	Assist in problem identification.
Mid-project	Identify potential process inputs to investigate in the project to determine which inputs have a significant influence on the process output.

Guidelines

Be sure to include project stakeholders in the brainstorming sessions for building the fishbone diagram.
If the standard categories of the causes are not appropriate for the problem, create new ones. Fishbone diagrams can include any type of cause you want to investigate.

How-to

Gather the project team and appropriate stakeholders for a brainstorming session.
For each category (surroundings, suppliers, skills, and systems), list all possible causes or process inputs. You may want to establish secondary categories for some or all of the primary categories, then list the causes or process inputs under the secondary categories.
Highlight causes (or inputs) that are deemed to be the most important by the team.
Record the causes in a fishbone diagram using the 4S template.

Note

Quickly brainstorm ideas in the brainstorming list and click-and-drag them to the diagram to create associations between related ideas. For more information, go to Generate a brainstorm list.