Problems always existed, and will surely come up in the future. It can be a technical defect, an organizational issue, or anything that holds a barrier between us and the desired state. The question will always be the same: how can we prevent problems before their occurrence, and if they occur, how can we solve them with the highest efficiency. Problem solving needs analytical thinking and creativity. Often thinking "out of the box" leads to success. As we solve the problems of the organization, we can both directly and indirectly improve business results.

Having an ordinary mindset, we might think, that the problem is solved when we only resolve a given issue. In this case, we do not take any effort to prevent its further recurrence, so besides correcting an undesired state, a major part of problem solving is the prevention of the failure in the future.

Problems can have many entities (technical defects, failure of a process, etc.) and different chronology (sudden, constant, repeating time-to-time, deteriorative over time, etc.). Depending on the consequences, the problem holds risk, and must be eliminated.

Generally in any industrial field, problems mean technical or organizational defects, that can diffuse to financial and prestige issues. During the history of quality management, several key techniques and methodologies were developed to foster and motivate analytical problem solving, thus creating direct and indirect value for the organization. Such examples are the Global 8D methodology, set into frame by Ford, or the PDCA (Plan-Do-Check-Act) Deming cycle, but we can also mention the 6 Sigma methodology, which also aims to resolve issues, leading to the improvement of business performance.

ISO 9001 standard requires to determine the root cause of nonconformities, to implement corrective and preventive actions and to review the effectiveness of all actions. The automotive specific IATF 16949:2016 goes further by requesting the application of a defined problem solving process, error-proofing and the spreading of counter-measures to similar products and processes.

Irrespectively of the affected field (technology, finance, etc.), the problem solving process has a general structure. All problem solving procedures and quality improvement methodologies (e.g. 8D, PDCA, 6 Sigma, Kepner-Tregoe, Shainin, etc.) have a logic sequence of basic tasks that rely on common sense. Problem solving always aims to understand the problem, identify and understand its cause(s), and eliminate the cause(s) by implementing and verifying effective corrective and preventive measures.

Based on the aforementioned sequence, the different methodologies can be put into a uniform grid (see chart).

In this section we will focus on the "8 Disciplines" method, which is most current problem solving procedure (methodology) in the automotive industry, however is can be used in every field, thanks to its logic sequence. 8D is a team based method, and a major part of continuous improvement. There are plenty of other methodologies as well, such as 6 Sigma, PDCA.

Many questions come up that we need to answer before and during solving a problem:

We will use best practices and effective tools to be able to answer these questions, going through the 8D steps, which are:

In the following part, we will go through the Eight Disciplines of Problem Solving.

Problem solving is never a one man show, but a teamwork. This is not just an empty sentence, but the reality. There are no complex problems that affect only one person, one group or one department. Establishing an effective team is necessary with the knowledge and expertise of relevant technology, processes, supporting quality methods, etc. In addition, having an 8D team provides dedicated resources and a sponsor. Of course there are problems, that shouldn’t be pumped up, and can be resolved by oneself (see table below), but these are usually not the complex issues.

Describing the real problem is the key for understanding the root cause(s) and for proper decision making. Fundamental understanding of the problem is the first step to be able to find its cause, and to eliminate it. Proper description must contain the following problem features and problem related questions:

By having the right questions and describing the problem / failure leads us to be able to provide usable information for the team (e.g. depicting failure patterns). This information will be crucial during step 4 (D4 – Root Cause Analysis).

In practice, customers usually see only the symptom, and only give these symptoms when communicating the defect, so understanding the fundamental problem that leads to the symptom can be difficult. Do not forget: at this phase of the problem solving, we do not know the root cause yet (see chart about the "cause – problem – symptom" interaction).

Important! The proper understanding and definition of the real problem (not symptom!) is crucial, otherwise the D4 (root cause analysis) will be everlasting. Hint: already start your convergent thinking and strategy creation how you want to solve the given failure (useful tools: IS/IS-NOT, Shainin Red X (R) tools and structure, e.g. solution tree, component search, etc.)

As it was written above, the detection point of the failure is an important information. The automotive industry has created the following failure types, depending on detection point of the failure in the supply chain:

It is the first physical action we take, however it’s a reactive one, used for mitigating the failure effect in the supply chain, instead of focusing on the elimination of the cause. We need to apply 100% effective containment until we implement a proven corrective action, which will be eliminating the root cause of the problem. After implementing a containment action, we have to maintain it by continuous monitoring and frequently review (it’s not enough if we verify it before its implementation, since what works on small scale, doesn’t surely function on large scale). Besides that, the information provided by the containment action can be helpful for investigating the root cause, by gathering valuable information about:

If preventive action is the "vitamin and healthy food" and corrective action is the "surgery", then containment action is the "first aid bandage".

Examples for immediate containment actions:

The fourth section of the 8D is aiming to find the real causes that lead to the problem and the symptom. Root cause analysis is one of the most difficult part of problem solving, as we have to investigate the complex aspects of the failure mechanism, we have to search for patterns, what has changed, what has caused the "variation". Luckily, there are several methods and tools available, which support us during this task.

The importance of effective root-cause analysis is crucial, as we cannot define and implement actions to eliminate the cause without finding it. Also, it might happen, that incorrectly performed root-cause analysis misleads us, and we define actions that are ineffective against the real cause. It is very important to do our analysis procedure unbiased. Prejudiced root cause analysis guides us to improper decisions. On top of that, we have to emphasize proper failure description (D2), as it is the basis of efficient root cause analysis.

We distinguish two layers of the root cause. The first, direct one is the technical root cause, while the deeper one is the management or managerial root cause (also called system root cause). Technical root causes mean the more direct causes that are near to the technical problem. To find the management root cause, we have to drill deeper into the system, organization, etc.

Generally, during investigating the cause effect relationships, we try to:

By analysing the root cause(s), we have to focus not only on the occurrence of the defect, but also on the non-detection:

Finding all root causes and all cause effect relations is a complex task, and it’s rarely an easy job, however during the 20th century many logical and transparent root cause analysis methods have been developed, such as:

In industrial environment, the origin of technical (and management) root cause can be originated from various sources. That is why having an 8D team is crucial to find these causes. In particular cases, the defect itself may be originated from the customer, due to misuse or mishandling, thus the involvement of the customer into the root cause analysis is important. The source of the technical cause (causing process) can be:

Depending on the identified root cause, finding the best solution in the form of corrective actions can happen in the frame of brainstorming by involving the concerned experts. During this phase, it is advised to note all possible solutions without immediately shooting down any of them. Gut rejection may lead to inefficient or completely wrong decisions.

Important points for defining effective corrective actions:

After defining possible corrective actions, the 8D team has to select the ones to be implemented, by setting up an action plan with deadlines and responsible team members.

Beside physical implementation, the actions must be documented in the relevant living documents (FMEA, CP, Work instructions, etc.).

Though the planned corrective actions were probably analysed up-front (before their implementation), the verification after the serial implementation is still a must. Again, the verification has two major purposes: verification of the effectiveness and getting to be assured, that no side effects came up. Corrective action is in close conjunction with possible preventive actions, they are quite often named together, such as CAPA (Corrective Actions and Preventive Actions).

It is strongly important to note, that the containment actions implemented in step three (D3) can only be stopped when the relevant corrective actions surely eliminated the root cause.

The intent of preventing failure occurrence is a systematic preventive approach. By using the tools of risk analysis, FMEA, manufacturing capability test, etc., we take up-front measures to eliminate the chance of a failure. Now the logic question comes up: why do we have a preventive actions block in our problem solving process, if the problem has already occurred?

The answer is simple: even if the problem has occurred, we don’t want it to happen again on other manufacturing lines, in other facilities, in other divisions. So the "preventive actions" block in the 8D process is focusing on the solutions against failure recurrence. The widely used tool to spread the knowledge of the failure and the solution is the Lessons Learned methodology.

The last point of the 8D report is the section for giving thanks to the team, and to summarize additional information that the team leader wants to emphasize.

Problem solving and root cause analysis needs analytical thinking, fact based proofs, filtering out irrelevant information, seeing coherences and correlations, avoiding bias in group works.

Containment actions are immediate and interim, but their importance is not negligible, and need planning and verification. It mustn’t be forgotten: the efficiency of visual inspection is only 80-90%.

Before starting the analysis of the root cause, we have to make sure of getting trustworthy information. Written and verbal information may also contain error, not only our measurement system. Such as we verify our measurement system with MSA, so we should validate the received information with plausibility checks.

By finding the technical root cause(s), do not stop there, but try to find any eliminate the management root cause(s) as well.

You can be firm about the root cause with theory, but you can only be completely assured after being able to reproduce the failure (one of the most basic principles of 8D and 6 Sigma methodology).

The importance of Lessons Learned is high to avoid failure recurrence. The best LL systems are ergonomically developed systems, providing prompt, fact based information. If we share only the failure mode and the root cause, it’s not a Lesson Learned. Good LL brief information always contains the solution as well.

To give a comprehensive hint list regarding problem solving, the following list contains some most important points you should consider: