Eight Disciplines Problem Solving Process
Eight Disciplines Problem Solving Process
There are four levels of problems which are generally encountered in an organization. These consist of (i) simple problems which can be solved by an individual, (ii) simple problems for which the answers are known (these can be termed as more like a task than a problem solving effort), (iii) difficult problems for which there are no known answers and which require more than one person/discipline for finding of their solution, and (iv) problems which have been around for some time but finding solution for these problems is critical for the organization.
The concept of problem solving is quite old. The industrial revolution had brought more complicated problems. For solving of these problems there was a requirement of a scientific approach to problem solving. Though such an approach was taught to specialists, but mostly, the problem solving has been left to the individuals. Some organizations started teaching standardized, team methods to the employees for increasing their problem solving efficiency.
Organizational structure is needed to support problem solving. Hierarchy of responsibility and proper lines of communication is required to be in place before effective, formal problem solving can begin. Generally there is adverse human dynamics when structure fails. Problem solving involves more than just following a few given steps. It requires a disciplined way of thinking and knowledge of certain tools, methods and principles.
Eight disciplines (8D) problem solving process is a method for solving of problems in the organization. This method was first developed and standardized by US Government during the Second World War. It was later popularized by the Ford Motor Company in the 1980s. 8D became a standard in the Auto, Assembly, Semiconductor and other industries worldwide. While the origin of the 8D problem solving process has been focused on manufacturing, it is being applied throughout the organization, from design to marketing of product and everywhere in between.
8D stands for the 8 disciplines or the 8 critical steps for solving the problems. The process is used to identify, correct and eliminate problems. The method is useful in product and process improvement. It establishes a standard practice, with an emphasis on facts. It is a highly disciplined and effective scientific approach for resolving chronic and recurring problems. The process is designed to find the root cause of the problem, devise a short term fix and implement a long-term solution to prevent recurring problems. It is used mostly by the professionals specially the quality personnel. In the 8D methodology, the main purpose is to identify, correct and eliminate recurring problems.
The 8D problem solving process is normally needed (i) when safety or regulatory issues are noticed, (ii) when there are a number of customer complaints which are regularly being received, (iii) when the warranty concerns have indicated greater-than-expected failure rates, and (iv) when internal rejects, waste, scrap, poor performance or test failures are present at unacceptable levels. The model of the 8D problem solving process has four arms namely (i) form, (ii) norm, (iii) storm, and (iv) perform.
8D problem solving process uses team synergy and provides excellent guidelines to identify the root cause of the problem, implement containment actions, develop and then implement corrective and preventive actions which eliminate the problem permanently. It isolates and contains the most basic causes of any undesirable condition at an early stage and prevents problem recurrence.
The 8D approach is used to solve critical, major, chronic and recurring problems. The 8D use is typical when (i) the complexity of the problem exceeds the ability of one person (an expert) to resolve the problem, (ii) when there is necessity that the communication of the problem resolution (during and after) is to go across the organization level, other departments and/or to the customers.
The strength of the 8D problem solving process lies in its structure, discipline and methodology. It uses a composite methodology, utilizing best practices from various existing approaches. It is a problem solving method which drives systemic change, improving an entire process in order to avoid not only the problem at hand but also other issues which can spring out from a systemic failure. The process is useful in product and process improvement.
8D problem solving process has a team oriented approach. When the team members cooperate in problem solving activities using a structured approach, the team becomes very effective at identifying symptoms, defining problems, establishing causes and taking actions which solve, prevent and lead to improvement. The team oriented approach establishes a permanent corrective action based on statistical analysis of the problem and focuses on the containment, origin of the problem by determining its ‘root cause’, and verification of the corrective actions. It requires statistical thinking, which means facing of the unpredictable, understanding of variability, and knowing of how to deal with it.
It normally takes several weeks to several months in order to solve a problem in the 8D problem solving process approach. It takes usually a minimum of four people from at least four different organizational areas (such as quality assurance, engineering, marketing, operations, and maintenance, etc.) to effectively apply the 8D team problem solving approach. The 8D team needs support of senior management for the allocation of time/resources and the authority to make the appropriate and required changes.
Although it originally comprised eight stages, or ‘disciplines’, it was later augmented by an initial planning stage. As a good plan is always important for the success of any process, so this initial step is not to be overlooked. The basics of the planning stage include figuring out what exactly the problem is which is required to be solved, who is going to be involved in the solution, and what other information/resources are going to be needed. Once this foundation is laid, the 8D process can proceed to get success.
As the name of the process suggests, there are eight disciplines included in this process, each designed to help to move a step closer to a successful conclusion. The eight disciplines are (i) creation of the problem solving team, (ii) describing of the problem, (iii) implementation of the containment action, (iv) identification and validation of the root cause through root cause analysis, (v) identification and choosing of the corrective action, (vi) implementation of the corrective action and their tracking for effectiveness, (vi) identification and implementation of the preventive action, and (viii) closing and congratulating the team. The methodology follows the logic of the PDCA (plan-do-check-act) cycle (Fig 1).
Fig 1 8D problem solving process and PDCA cycle
Creation of the problem solving team
Team formation is the first discipline of the 8D approach. This discipline is very important as the 8D is based on the foundation of team synergy. This first discipline establishes a small group of people with the knowledge of the process/product. The group of people is allocated time, authority and skill in the required technical expertise to solve the problem and implement corrective actions.
The team approach is important since (i) a team can perform more effectively than individuals trying to solve the problems, (ii) a group of people can communicate and think creatively, and (iii) brainstorming as a group can stimulate ideas giving the team a better perspective of the problem.
The 8D team consists of 4 to 8 persons who are closely related to the problem. It usually involves people from different functions/departments in the organization coming together to solve the common problem. A senior person (an executive sponsor who is not a working team member) is ultimately responsible for fixing the problem. The team leader (usually from quality assurance or production department) is the person who coordinates the entire 8D project through-out all of its disciplines. The person makes sure the team is on track and all team members are working together to resolve the problem. The team includes a person having knowledge of 8D problem solving process guides the team through the 8 disciplines using the appropriate quality tools at each step. A person having the knowledge of the subject matter is also part of the team. The team is supported by a group of supporting persons. These supporting persons have practically experienced the problem and understand the pain it causes.
The team leader has several responsibilities. He is to generate a list defining the team structure in order to ensure that a team is actually formed for the 8D project. This list is also useful to define the function/role to be played by each team member in the 8D project. He is required to schedule meetings periodically to review progress of the 8D project and discuss action items in order to meet all expectations. He is to maintain minutes of the meeting documenting all which happens in the meeting. Meeting minutes can include (i) team progress, (ii) key decisions reached in the meeting, (iii) planned versus actual completion dates for all actions, and (iv) actions to be taken by a team member which include when, where, and how. Team leader can also change any member’s roles and responsibilities once the problem statement is further refined and understood. Team members are to complete their actions and report back to the team leader.
Describing of the problem
Describing of the problem starts with a well thought out problem statement. The problem statement is required (i) to communicate the scope of the problem which the team is working on and to get the team focused on it, (ii) to provide information relevant to the problem such as the data and information on what the problem is and what the problem is not, (iii) to clarify the role the team is to play (to determine root causes and to implement or to recommend a solution), to specify the deadline, and to include the monetary limits for the team, (iv) to lay down the expectations from the team and deliverables which are required to be measured, and (v) to be the output of a process used to amplify the problem statement in terms of who, what, why, where, when, and how big (how much, how many, how often there is going to be level of pain). Tools to be used for describing of the problem are data collection done for the background information (is / is not analysis), and Pareto charts.
Implementation of the containment action
The containment action is an interim measure which is like a ‘First-Aid’. It is put in place for preventing the effect of the problem or preventing the full effect from impacting customers and/or employees while a permanent solution is being developed and implemented. Interim containment normally includes quality alerts, inventory purge and inspection, sorting of bad parts from good ones, adding short term operations, review of the current procedures, use of the additional work-force on the process, and additional inspection and testing, etc. The interim containment is necessary since while the problem solving team is working on to find the root cause of the problem and implement corrective actions, there are expected that some defective products are produced. It is important to prevent these defective products from reaching the customer. Interim containment ensures that the defects are contained in the organizational facility till the problem is completely solved. If defective products reach the customer, it can result in field failures, warranty claims and customer complaints.
The interim containment measures are to be verified that they are working. They are to be appropriate and effective. The impact of the interim containment measures is to be tested to ensure that no additional problems are being created. The actual additional costs of the containment measures are to be known. These costs are to be verified to ensure that these costs are reasonable costs. The interim containment actions are not to cover the gravity of the problem thus reducing the need for a permanent solution. Interim containment actions if left alone become part of the process. It can become hidden actions which do not add any value, but add only to cost. In lean manufacturing, this is a waste which is needed to be removed. It is to be understood that containment action is a temporary action and not a solution, nor it is a corrective action. Containment actions can be implemented internally (local inventory, work in progress, finished goods), or externally such as at the suppliers’ end or at a customer end depending on the nature of the problem.
Identification and validation of the root cause through root cause analysis
The core of the 8D problem solving process is the defining of the root causes of a problem. This is generally the most difficult feature of the problem solving process. If the root causes of the problem are obvious, then the problem would have been solved already. There are normally two groups of causes at work when there is a problem. In the first group, the causes which appear to be the problem are often symptoms, not the root causes. In the second group, the specific causes which allowed the apparent symptoms to occur are the root causes and often buried deep in the process.
The tools which are generally used are Pareto charts, Affinity diagram, Brainstorming session, 5-Whys process, Fishbone diagram, Fault Tree analysis (FTA), statistical analysis, ANOVA ( analysis of variance), Regression analysis, Hypothesis testing, GR&R (gauge repeatability and reproducibility) analysis, Flow charts, audits, and FMEA (failure mode and effect analysis) etc.
During the root cause analysis, it is to be ensured that the cause identified is not just a symptom but is the actual root cause. If the symptom is cured then the problem can recur. Root cause analysis is to ensure that all the identified causes explain all that is known about what the problem is, as well as all that is known about what the problem is not. That is it is to ensure that the root cause is found fit both for the reasons for the problem as well as for the reasons which have not caused the problem. If the cause which is being tested does not fit both, then it is probably not the root cause. Further, the root cause identified is required to be verified. Verification can need a series of confirmation runs. If it is possible to induce the failure, then the failure mode is to be turned on/off and then it is to be found out how it happened and how it got removed.
Identification and choosing of the corrective action
The solution or solutions very often become clear once the root cause is known. However, sometimes, a systematic approach is needed to use the root cause analysis to develop a solution. If the solution is clear, then the best solution or mix of solutions are selected which lead to a robust, yet cost-effective, solution to the problem. If solutions are not yet evident, then the data trail is required to be followed. When solutions are not clear, then it is often due to the reason that the root cause has not been found. Standards for choosing the best solution include (i) the solution is to be practical which means that it is possible to implement the solution in practice, (ii) the solution is to be feasible, (iii) implementation and using of the solution is to be cost effective, (iv) the identified solution is to be robust so that it does not fail when used in production, (v) The senior sponsoring executive is to be fully convinced so as to totally accept the permanent corrective actions and facilitates their implementation.
While finding the corrective actions for the problem there are some points which are required to be checked. It is to be ensured that the developed solution consider the practical aspect of the production. During the development of the corrective actions, the capability of manufacturing equipment and the workmen is to be considered. Also the quality of the available materials (including raw materials) is to be kept in mind. The developed solution is to pass the tests of practicality, feasibility and cost effectiveness. The solution is to be robust and capable of preventing a recurrence of the problem. The ROI (return on investment) or the payback of the solution is to justify the cost of implementing the solution. Also, the solution is to be capable of getting implemented within the required time deadline. If there is a requirement of training the workmen, the solution is to include the plans for the same.
Validation of the solution is also very important. It is necessary to establish that the solution has capability to make the problem go away without leading into other unwanted issues. That is reason that the 8D problem solving team tries out the solution with small quantities first to verify its effectiveness. A design verification test (DVT) and/or a reliability demonstration test (RDT) are normally required depending on the solution. Usually the solution is first tried on small lots to validate whether it has indeed solved the problem prior to full implementation.
Implementation of the corrective action and their tracking for effectiveness
Once the solution has been developed for the problem and its implementation has been approved, the next step is to create an action plan for the implementation of the corrective action. The action plan is to outline the steps which are needed to implement the solution, the persons who are responsible for the implementation, and time period for implementation. A simple action plan only documents all of these requirements. A complex solution needs more thorough planning and documentation.
For the action plan, there are some check points which are to be ensured. The first check point is that whether a simple action plan is adequate or there is a need for the complex action plan. If a complex action plan is needed, then the detailed activity plans, Gantt charts and PERT charts are required to be developed. Part of implementing a solution is to document new procedures or making of the changes to the existing procedures as well as making of the changes which relates to the organization’s quality system. Also training to support the new system (s) is to be provided to the workmen.
The action plan is then put to use. After the new procedures and the revised processes are used for some period, it is likelihood that there are some new suggestions for the improvement. These suggestions are required to be assessed and based on the useful suggestions the needed process adjustments are made. The necessary documents are also revised and the workmen are retrained for those adjustment.
Identification and implementation of the preventive action
The job of a problem-solving team also includes the identification and implementation of the preventing action. Preventing recurrence is an important part of a problem’s solution. To prevent recurrence of the problem, the team is required to verify that the outcome of the action plan made works and the team is to validate that the outcome is on-target. Verification consists of testing that the solution produces the desired outcome. Validation is needed to ensure that the outcome really solves the problem.
There are check points to achieve this. First check point is that action plan is to be verified that it works. The outcome which is to be validated is to be on-target. The checking includes that the action plan results have been documented, related procedures have been updated, and the corresponding changes to any affected quality system elements have been made. An audit system is needed to be established to assess the use and effectiveness of the solution to ensure that the gains are maintained. The results are then leveraged to prevent occurrences of like problems in all similar operations. Also, it is to be ensured that all the necessary controls for the solution are in place. The tools used for the preventive action include control charts, control plans, histogram, capability analysis, FMEA, and GR&R analysis.
Closing and congratulating the team
Once the team has completed implementing the solution and ensured that the solution works, all team members deserve to be congratulated. Team members need to know that their efforts are appreciated and that the organization knows about their accomplishments. The organization management is required to recognize the team for their efforts which it has made in a timely manner. The project team, in turn, is to recognize those who have provided the team with support and assistance.
Benefits and limitations of 8D Problem solving process
The 8D methodology is commonly used process since it provides a consistent, easy-to-learn and thorough approach to solving whatever problems which can arise at various stages during the production process. When properly applied, it gives several benefits. These benefits include (i) improved team oriented problem solving skills rather than reliance on the individual expertise, (ii) increased familiarity with a structure for problem solving methodology, (iii) creation and expansion of a database in the organization of past failures and lessons learned to prevent problems in the future, (iv) better understanding of the use of the basic statistical tools needed for problem solving, (v) improvement in the effectiveness and efficiency at problem solving, (vi) team members get a practical understanding of ‘root cause analysis’ tool, (vii) problem solving effort can be adopted into all the processes and methods of the organization, (viii) improved skills for implementing corrective action, (ix) better ability of the team members to identify necessary systemic changes and subsequent inputs for change, and (x) more frank and open communication in problem solving discussion which increases the process effectiveness.
However, the 8D problem solving process is not effective for (i) non-recurring problems or those problems which can be solved quickly by individual effort, (ii) problems which have known root causes, (iii) making a decision between different alternatives, and (iv) problems where the simplest and most obvious solution is likely to be the best or adequate solution.