Tool 26: Cause and Effect Diagram Adding Cards (CEDAC)

AKA

Bulletin Board Fishbone

Classification

Analyzing/Trending (AT)

Tool description

Developed and first introduced in 1978 by Sumitomo Electric Industries of Japan, the cause and effect diagram adding cards (CEDAC) is a fishbone diagram that typically displays major, generic categories such as people, methods, materials, equipment, measurement, and environment that cause an effect, often perceived as a problem. This diagram is used to systematically analyze cause and effect relationships and to identify potential root causes of a problem. An additional feature of adding cards by those outside the team allows the capture of more ideas from others in an expanded involvement in the problem-solving process. Once the basic diagram is completed and posted, cards or notes indicating more causes or ideas are attached.

Typical application

• To assist a team in reaching a common understanding of a complex problem and to share this information with others for more input.

• To expand the team's thinking and to consider all potential causes.

• To post and share a completed cause and effect diagram (CED) for the purpose of allowing others to add potential causes or ideas.

• To define the major categories or sources of root causes.

• To organize and analyze relationships and interactive factors.

• To identify factors that could improve a process.

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

links to other tools

before

• Cause and Effect Diagram (CED)

• Brainstorming

• Brainwriting Pool

• 6-3-5 Method

• Five Ways

after

• Problem Specification

• Work Flow Analysis (WFA)

• Process Analysis

• Countermeasures Matrix

• Pareto Chart

Notes and key points

• This tool is an expansion of the cause and effect diagram (CED).

• Generic category designations may be substituted. Example: Procedures for methods, or facilities for requirement, etc.

• Do not overload categories. Establish another category if more detail is desired.

Step-by-step procedure

• STEP 1 Reach consensus on a problem to be analyzed. See example Missed Reproduction Schedules.

• STEP 2 Determine the major categories and place one in each category box.

• STEP 3 Brainstorm possible causes for each category and enter in a fishbone fashion by drawing arrows to the main arrow (category), as shown in the example.

• STEP 4 Continue to ask questions using the Five Whys tool to search for root causes. Insert and connect potential causes to the various other contributing factors.

• STEP 5 When the team feels that the diagram is complete, a final and much larger diagram is drawn.

• STEP 6 The diagram is posted in a hallway or on bulletin boards with an invitation for others to examine and possibly add their causes or ideas on available cards or Post-its to the respective categories on the diagram.

• STEP 7 After a specified period of time, the diagram is removed and revised to include the additional information. A completed, smaller diagram is reposted with a thank you note.

• STEP 8 The team now advances to the next step of further analysis, additional data collection, and problem solving.

Example of tool application