Root Cause Analysis explained: Basics, a Step-by-Step Guide and Example

A root cause analysis helps you not only solve the visible problem, but above all identify the true cause. This is important because quick fixes often only address the symptoms. The problem may seem to disappear for a while, but it will return later. With an RCA, you investigate step by step what happened, why it happened, and what corrective actions are needed to prevent it from happening again.

In this article, you’ll discover what a root cause analysis is, when to use RCA, and how to apply the method step by step. You’ll also learn about helpful approaches and tools, such as the “5 Whys,” the fishbone diagram, barrier analysis, change analysis, and the Kepner-Tregoe method. In addition, you’ll see how RCA is applied in practice in manufacturing, IT, and safety. Enjoy reading!

What Is a Root Cause Analysis?

A root cause analysis, also known as RCA, is a problem-solving method aimed at identifying the causes of problems or events. This systematic approach aligns with the work of Rooney and Vanden Heuvel (2004). They describe root cause analysis as a method for defining problems, investigating causes, and moving from treating symptoms to achieving structural improvement.

The practice of RCA is based on the belief that problems are best solved by correcting or eliminating their causes, as opposed to other approaches that focus on addressing the symptoms.

RCA is often used when something goes wrong, but it is also employed when things are going well. More on this proactive approach to problem-solving later. Root Cause Analyses, as well as incident investigations and other forms of problem-solving, are fundamentally linked to the following three questions:

• What exactly is the problem?
• Why is this problem occurring?
• What can be done to prevent this problem from happening again?

What is the purpose of a Root Cause Analysis?

Corrective actions are taken to address the underlying causes with the aim of minimizing the likelihood of the problem recurring.

It is unrealistic to think that a single intervention can completely prevent recurrence. For this reason, an RCA is often viewed as an iterative process. This analysis is used as a tool for continuous improvement. Andersen and Fagerhaug (2006) also emphasize that Root Cause Analysis must be conducted systematically. Investigating causes, selecting appropriate measures, and monitoring the results form a recurring improvement process.

Proactive Approach to Problem Solving

When root cause analysis is used for the first time, it is a reactive way to identify and solve problems. This means that an analysis is conducted after a problem or event has occurred. As experience with root cause analysis is gained, the approach transforms from reactive to proactive.

In practical terms, this means that, based on this problem analysis, one would be able to predict certain events or anticipated problems so that one can take preemptive action . A root cause analysis is not a strictly defined methodology. There are many different tools, processes, and philosophies that have been developed based on root cause analysis.

Nevertheless, five problem analysis approaches can be identified that are recognizable in practice:

• Root cause analysis based on safety – Its origins lie primarily in accident analysis, safety, and healthcare.
• Root cause analysis, based on production – Its origins lie primarily in the fields of quality control and industrial manufacturing.
• Root cause analysis, based on processes (Process) – This is an extension of the approaches used in production and business processes.
• Root cause analysis, based on failures – This originates in engineering and maintenance.
• Root Cause Analysis, based on systems (Systems) – This approach originated from a fusion of previous approaches, combined with ideas from change management, risk management, and systems analysis.

Despite the apparent differences in objectives and scope between the approaches, there are some general principles that can be considered universal.

It is also possible to define a general process for conducting a root cause analysis.

Where is Root Cause Analysis applied in practice?

Root Cause Analysis is applied in a wide range of fields. Below are a few examples of situations where an RCA can make a difference.

A root cause analysis in a production environment

When an industrial machine malfunctions, an RCA can identify the cause of the malfunction. If it turns out that a fuse has blown, the fuse can be replaced and the machine restarted, but the machine will stop working again after a while.

By conducting an RCA, it is discovered that the problem lies with a pump in the automatic lubrication mechanism. By identifying the root cause of the failure through an RCA, appropriate corrective action can be taken to prevent the same problem from recurring.

From Visible Symptom to Root Cause

In this example, the blown fuse is the visible symptom. Replacing the fuse allows the production machine to be restarted. However, the solution is only temporary because the cause of the overload has not yet been eliminated.

The production team therefore gathers additional information. Fault reports, maintenance reports, production times, and the motor’s power consumption are compared. This reveals that the machine mainly shuts down after longer production cycles. The motor then becomes overloaded and draws too much current, causing the fuse to blow.

Further investigation reveals that the automatic lubrication system is not functioning properly. The pump does not deliver sufficient pressure, resulting in inadequate lubrication of moving parts. Resistance within the machine increases, and the motor has to work harder and harder. The malfunctioning pump thus turns out to be the underlying cause of the recurring failure.

The pump is replaced, but that is not the end of it. The maintenance protocol is expanded to include checks of lubrication pressure and flow rate. A warning signal is also set up to detect anomalies in the lubrication system at an early stage.

After the adjustments, the team monitors the machine’s performance for eight weeks. They look for new malfunctions, power consumption, and the operation of the lubrication system. When the fuse does not blow again and the measured values remain stable, it can be concluded that the corrective measures are effective.

This example illustrates why a Root Cause Analysis goes beyond simply repairing a visible defect. By collecting data, investigating causes, and verifying the effectiveness of corrective actions, the likelihood of the same problem recurring is reduced.

Information Technology

RCA is also used in IT to identify the root causes of problems. One example is the computer security management process, where root cause analyses are used to investigate security breaches.

Safety

RCA is also used in the field of safety and health. Examples include medical diagnoses, identifying the source of an epidemic, accident analysis, and occupational health.

How do you perform a root cause analysis? A concrete step-by-step plan to get started right away

The general process behind a root cause analysis consists of a number of basic steps.

Step 1: Define the problem

Define the problem or provide a factual description of the event. To do this, use both qualitative and quantitative information (nature, scale, locations, and times) from the relevant data.

Step 2: Gather information

Gather data and evidence, classify it, and organize it along a timeline of events leading up to the ultimate problem or incident. Any notable deviation in behavior, condition, action, or inaction should be noted on the timeline.

Step 3: Apply the 5 Whys method

Keep asking “why” to trace the effects back to their causes, documenting the causes at each step in the sequence leading to the defined problem or event. Read here to learn more about this method.

Step 4: Classify the causes

Classify causes within the causal factors related to a critical moment in the sequence, including the underlying causes.

Step 5: Apply chronology

If there are multiple causes—which is often the case—indicate this, preferably in chronological order to facilitate a later selection. Identify all other harmful factors.

Step 6: Respond

Devise corrective actions or improvement measures that, with a high degree of certainty, can prevent the causes from recurring. Investigate whether this can be simulated in advance so that the potential effect becomes apparent, including in relation to other underlying causes.

Step 7: Develop Solutions Based on the Root Cause Analysis

Devise effective solutions that can prevent the recurrence of the causes, with the agreement of the colleagues involved. These solutions must also meet the intended goals and objectives and must not cause new or unforeseen problems.

Step 8: Implement solutions

Implement the proposed solutions (corrective actions) on which there is consensus.

Step 9: Monitor effectiveness based on the Root Cause Analysis

Closely monitor the effectiveness of the proposed solutions (corrective actions) and make adjustments as needed.
Important to consider:

• Other methods for problem-solving and prevention may be useful.
• Identify any remaining causes that are also harmful factors in the process and address them.
• Note: Steps three, four, and five deserve special attention. If potential and underlying causes are not sufficiently investigated, there is a risk that the chosen measures will only address the visible symptoms.

The analysis steps above help determine the root cause of the problem. Corrective actions are then developed to address this cause and reduce the likelihood of recurrence.

Supporting Tools and Methods for Root Cause Analysis

Below is a list of some well-known RCA techniques:

Barrier analysis

This RCA technique is often used in industrial settings. It was developed to trace energy flows, with a focus on potential barriers to those flows, in order to determine how and why these barriers do not prevent the energy flows from causing damage.

Current Reality Analysis

This complex but powerful method (Current Reality Tree) by Eliyahu M. Goldratt is based on representing causal factors using a tree structure.

This method is governed by logical rules. It begins with a short list of the undesirable things we observe around us, which then lead to one or more underlying causes.

Change Analysis

This investigative method is often used in the event of problems or accidents and shows, from various perspectives, how the problem occurred.

5x Why (Five Times Why)

With the Japanese “five times why” method, the question “why” is asked five times. This problem-analysis technique was originally developed by Sakichi Toyoda, who used it to identify the causes of problems within Toyota’s production process.

Serrat (2017) describes the 5 Whys method as an accessible technique for probing deeper to uncover underlying causes. By not stopping at the first explanation, the likelihood of addressing only the visible symptom is reduced.

Combining Root Cause Analysis with the SCORE Model

A Root Cause Analysis focuses primarily on identifying the underlying cause of a problem. The SCORE model by Dilts and Epstein can then provide additional structure. The model helps link the identified causes to a desired outcome, available resources, and the expected effects of a change. This results in a broader analysis that not only explains why the problem exists but also points the way toward an appropriate solution.

Fishbone Diagram

The fishbone diagram is also known as the Ishikawa diagram or cause-and-effect diagram. Project managers often prefer to use the fishbone diagram when conducting an RCA.

Ishikawa’s work (1986) demonstrates how cause-and-effect diagrams can help organize potential causes in a clear and structured manner. This allows a problem to be examined from multiple perspectives and prevents a team from too quickly identifying a single explanation as the root cause.

Kepner Tregoe Method

The Kepner Tregoe Method is a fact-based approach in which potential causes are systematically ruled out to determine the true cause.

RPR Problem Diagnosis

This is an ITIL-aligned problem analysis method for diagnosing IT problems.

Five Core Principles Common to Every Root Cause Analysis

Although there are many different approaches to Root Cause Analysis, most methods boil down to the following five core principles.

Identification and Description

Problem statements and event descriptions are very useful and are often required to properly conduct an RCA. A system failure is an example of a problem where this is particularly important.

Chronology

Root Cause Analysis must establish a sequence of events or a timeline before the relationship between causal factors can be understood.

Differentiation

It is important to distinguish between the root cause, causal factors, and non-causal factors. This is done by correlating the sequence of events with the scope, nature, and timing of the problem. One way to identify underlying causal factors is through the use of clustering and data mining.

Causes

Finally, researchers must use the sequences of events to create an additional sequence of events that actually caused the problem. This is then converted into a causal graph.

To be effective, a root cause analysis must be conducted systematically. This type of problem-solving is often a team effort. Consider, for example, the analysis of airplane accidents.

To this end, researchers’ conclusions and identified causes must be supported by documented evidence.

Corrective Actions Based on Root Cause Analysis

Developing and implementing corrective actions follows the root cause analysis. Root Cause Analysis helps identify the primary cause. Subsequently, measures are selected to address this cause and prevent recurrence.

Nevertheless, it is an important step that is incorporated into virtually all forms of RCA. This step therefore involves implementing long-term corrective actions to ensure the problem does not recur in the same way as before.

Okes (2019) explicitly links Root Cause Analysis to problem-solving and corrective actions. A problem is only structurally addressed once the underlying cause has been investigated, the selected action has been implemented, and its effectiveness has been verifiably monitored.

Root Cause Analysis Training

There are various types of training courses available for managers and others for whom conducting a proper Root Cause Analysis is important. These courses are ideal for people who need to understand the terminology and process of Root Cause Analysis for professional use.

Participating in such training helps participants understand how important it is to determine the cause of a problem to ensure it does not recur. In addition, these courses help identify common obstacles and challenges encountered when conducting a Root Cause Analysis.

Root Cause Analysis Summary

A Root Cause Analysis (RCA) is a method for identifying the root causes of various problems.

There are several methods and techniques used for this purpose: Fishbone Diagram, the Five Whys method, Barrier Analysis, and the Kepner-Tregoe method.

Although they all differ slightly from one another, the essence of the method can be summarized in three questions: What is the problem? Why is this problem occurring? And what is being done to prevent this problem? In practice, RCA is applied in manufacturing facilities, in information technology, and in the health and safety sector.

Five elements are crucial when conducting an RCA and are always present. First, it is essential to provide a description and explanation of the events leading up to the identification of the problem.

In addition, it is important to establish the correct chronology of these events. Next, a clear distinction must be made between the root cause, causal factors, and non-causal factors.

Afterward, investigators must determine the sequence of events that almost certainly led to the problem.

The final step typically involves implementing corrective actions. Although this is not a formal part of the RCA, this step is crucial to ensure that the problem does not recur in the same way in the future.

Tip: Want to get to the heart of complex problems even more effectively? Combine root cause analysis with other powerful methods such as Problem Tree Analysis, the CATWOE model, or the Ishikawa Diagram. These techniques help you gain insight into underlying causes, stakeholder perspectives, and systematic relationships. Discover how these models reinforce each other in your analysis process!

Recommended books and publications on Root Cause Analysis

Root Cause Analysis helps identify the true cause of a problem, rather than merely addressing visible symptoms. The method is widely used in quality management, process improvement, manufacturing, IT, safety, and continuous improvement. By systematically investigating causes, organizations can implement more effective corrective measures and prevent the same problem from recurring. The books and publications listed below provide additional insight into Root Cause Analysis, the 5 Whys, cause-and-effect diagrams, quality improvement, corrective action, Lean Six Sigma, and structural problem-solving.

1. Andersen, B., & Fagerhaug, T. (2006). Root Cause Analysis: Simplified Tools and Techniques. Milwaukee, WI: ASQ Quality Press. → This book provides a practical foundation for Root Cause Analysis. It is relevant because it demonstrates how teams can systematically investigate causes using tools such as cause-and-effect diagrams, process analysis, and other quality tools.
2. Gano, D. L. (2011). Apollo Root Cause Analysis: A New Way of Thinking (4th ed.). Yakima, WA: Apollonian Publications. → Gano describes a structured approach to analyzing cause-and-effect relationships. This book aligns well with Root Cause Analysis, as it helps readers look beyond assumptions and examine problems based on evidence, conditions, actions, and underlying system factors.
3. Ishikawa, K. (1986). Guide to Quality Control. Tokyo, Japan: Asian Productivity Organization. → Ishikawa is important to quality thinking and cause-and-effect analysis. His work is relevant to Root Cause Analysis because visually organizing possible causes helps to view problems more broadly and avoid jumping to a single explanation too quickly.
4. Latino, R. J., Latino, K. C., & Latino, M. A. (2016). Root Cause Analysis: Improving Performance for Bottom-Line Results. Boca Raton, FL: CRC Press. → This book links Root Cause Analysis to performance, reliability, and financial impact. The source is useful because RCA only truly adds value in organizations when causes are translated into concrete improvement actions and measurable results.
5. Okes, D. (2019). Root Cause Analysis: The Core of Problem Solving and Corrective Action (2nd ed.). Milwaukee, WI: ASQ Quality Press. → Okes clearly explains how Root Cause Analysis relates to problem-solving and corrective measures. This book is valuable because it demonstrates that a problem is only structurally resolved when the cause has been addressed and the corrective measure is demonstrably effective.
6. Rooney, J. J., & Vanden Heuvel, L. N. (2004). Root Cause Analysis for Beginners. Quality Progress, 37(7), 45–53. → Rooney and Vanden Heuvel provide an accessible introduction to Root Cause Analysis. This publication is relevant because it clarifies how RCA teams can define problems, investigate causes, and make the transition from treating symptoms to achieving structural improvement.
7. Serrat, O. (2017). The Five Whys Technique. In Knowledge Solutions (pp. 307–310). Singapore: Springer. → Serrat describes the 5 Whys as a simple technique for probing deeper into underlying causes. This aligns well with Root Cause Analysis, because repeatedly asking “why” helps prevent getting stuck on the first visible explanation.
8. Solé, M., Muntés-Mulero, V., Rana, A. I., & Estrada, G. (2017). Survey on models and techniques for root-cause analysis. arXiv. → This publication provides an overview of models and techniques for root cause analysis, particularly in more complex digital and data-driven environments. The source is relevant because modern organizations often deal with large amounts of data, interdependencies, and real-time systems in which causes are less immediately apparent.
9. Souza, R. V. B. de, Carpinetti, L. C. R., & Santos, F. C. A. (2020). Application of the 8D Method in the Automotive Industry: A Case Study. Production, 30, e20190086. → This case study demonstrates how Root Cause Analysis is applied within the 8D method in the automotive sector. This is valuable because RCA is often part of broader problem-solving methods that combine temporary measures, cause analysis, corrective actions, and safeguards.
10. Wilson, P. F., Dell, L. D., & Anderson, G. F. (1993). Root Cause Analysis: A Tool for Total Quality Management. Milwaukee, WI: ASQ Quality Press. → This book situates Root Cause Analysis within Total Quality Management. The source is relevant because RCA is not merely a standalone technique but can be part of a broader quality approach centered on learning, improvement, and prevention.

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Original publication date: August 15, 2010 | Last update: August 6, 2026

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