Root Cause Analysis

Contents 1 Applications 2 Procedures 3 Instructions 4 Example 5 Reference

A technique used to identify the conditions that initiate the occurrence of an undesired activity or state. Once the root causes are identified, steps to eliminate them can be determined. The result of this technique can be summarized using Ishikawa Diagrams. The key to applying the technique is to take problems expressed by the customers (not perceived problems) and determine if the statement sounds like an effect, a problem, or a cause. Remedies should be aimed at the root causes and not the problems or the effects.

Root Cause Analysis will provide the identification of all true causes, not symptoms, and an illustration of the interplay between causes/chain of related causes.

Applications

• To display characteristics of a given situation or problem.
• To brainstorm or identify potential causes, areas for further investigation, and/or solutions.
• To depict what needs to be in place to enable a given outcome or result (see Ishikawa Diagramming, positive Ishikawa).
• To help cross-functional organizational units understand interaction relationships.

Procedures

1. Review all candidate problems.
2. Remove duplications.
3. Reprint problems.
4. Review each item in the consolidated problem list and ask: "Is this a cause, or does this sound like an effect?," then continue to explore the chain of causes by asking: "Why? Why? Why?" to separate out problems from symptoms.
5. Exhaust the list of possibilities to discover additional causes and effects.
6. Circle or highlight the most probable causes, being careful not to include symptoms.
7. Discuss and prioritize for analysis/solution generation.
8. Validate against teammates, raw notes, gut hunches, and other information collected and available to the team.

Instructions

To start the Root Cause Analysis, review all candidate problems from the consolidated lists, obtained during the interview process (if available, see Problem Analysis). Remove duplication and combine like problem statements to synthesize the list into a manageable size. (Assign original problem numbers for tracking.) Reprint the problem statements, cut them into individual strips, and tape the strips to a flip chart or board for review. Construct an overall problem, main effect, or customer satisfier statement.

Review each item in the consolidated problem list, using Brainstorming and Facilitation, and ask: "Is this a cause or does this sound like an effect?" Focusing on causes, trace the chain of causes by asking the questions "Why? Why? Why?" until a root set of causes are determined. Ensure that causes are separated from their effects and that problems are separated from symptoms. A helpful way of determining if something is a cause or effect is to say the phrase, "CAUSE 1, therefore, PROBLEM STATEMENT, therefore, EFFECT." If that phrase makes sense, then you are on the right track. Or ask "Why?," which will lead to a root cause, and "So what?" which will lead to the effect of the problem.

There are three types of graphic representations that can be used to display the results of a Root Cause Analysis. The Cause and Effect Diagram is shown in Figure 1. An alternative cause and effect representation is the mind map. A more popular diagramming technique is the Ishikawa diagram, shown in Figure 2 (see Ishikawa Diagramming).

Example

Root Cause Analysis

Reference

1. Kazuo Ozeki. Tetsuichi Asaka, Handbook of Quality Tools, The Japanese Approach. Productivity Press, 1990.