The true value of the 8 disciplines of problem solving methodology is that it contains all of the important facets of modern problem management. Containment, Root Cause Analysis, Correction and Prevention are all covered using 8D problem solving steps.
Not long ago, a preliminary step (D0) was added to the 8 disciplines of problem solving structure. This step is primarily used to determine if your organization needs to utilize this more robust 8D structure or will the 5 step approach suffice. Conditions such as type and depth of issue, available metrics, commitment to determining the root cause, and customers affected should be considered as part of D0.
Determine the personnel required for the resolution of the current issue. Generally, a cross-functional team works best, but it's more important to ensure the correct people are on your team than it is to have a true cross-functional team. Determine your team's leader.
Provide as much detail regarding the current issue. Writing an outstanding problem statement is critical to the success of your problem solving efforts.
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Determine the impact of the customer's issue within your organization. Identify all possible suspect material and segregate that material for further review. List the date codes, lot numbers, etc. that are considered suspect. Determine a method that clearly shows the customer that all product shipped from this date was inspected and known to be acceptable.
D4 is the important and most difficult step of the 8 disciplines of problem solving.The team investigates the problem and begins to develop theories regarding where and how this issue occurred. Common methods for root cause analysis are:
Data Mining- investigating historical data for further information. Learn more about analysis of data.
Pareto Charts- this prioritization tool assists with decision making and resource planning by showing exact counts of the types of issues measured.
Brainstorming- a group technique useful for the creation of many possible root causes.
Fishbone Diagram- (also known as an Ishikawa Diagram or Cause and Effect Diagram) a tool that formats potential causes into distinct categories.
Also in the D4 step, your team determines the "escape point," that is, where in your process did this issue fail to get identified. As you follow the process backwards, you identify the location within your system that the root cause should have been identified but wasn't.
The team must be able to verify that they have indeed identified both the root cause and the escape point, and be able to take action upon the root cause. Returning to the process, the team should be able to make the issue come and go at will, indicating verification of root cause.
After verifying the root cause, the team assembles to generate potential PCAs. The team will consider topics such as: customer satisfaction, cost, elimination of the root cause, and others when attempting to choose the best PCA from the list of potential PCAs.
Use the selected PCA from D5. Implement this solution. Like in D4, the team should be able to make the problem come and go at will by alternately applying and removing the PCA. Continue to measure the process to ensure effectiveness.
Sustain the Gains! Regularly follow up on the process measures, again to ensure effectiveness and prevent backsliding. Update all documentation in your QMS. Mistake-proof the process if possible. Identify any potential areas where the same issue could occur and implement the same or similar PCA in those areas.
D8 is the most underutilized of the steps in the 8 disciplines of problem solving. While most companies will obtain formal sign-offs for the 8D structure, some fail to commend the team participants for the excellent work they accomplished. It is through this feedback that the team members feel appreciated, making them likely participants for the next issue (when it develops).