Root cause analysis is a structured process designed to find what, how, and why an event occurred. Only when you know the answer to these questions, you will be able to determine the corrective measures to prevent a recurrence.
A root cause is an underlying cause that management has control to fix, and recurrence prevention is possible by the application of effective recommendations. RCA drills deeper than symptoms to find the underlying action and conditions that led to the undesired situation. The goal of RCA is to identify one or two reasons that, if corrected, will reduce recurrence. RCA has four general steps.
Understand the problem
Understanding why an event occurred is critical for effective corrective actions. Just as with PDCA, problem definition is the most important part of the RCA process. Use a team approach whenever it is possible. It depends on the nature of the problem, but multiple heads are better than one. Get the background of the current situation and state the problem in clear, concise terms.
Common errors in describing problems are stating a solution in the problem statement, blaming others, and vague problem statements.
When you understand the problem, it is easier to identify what type of data you need to find the root cause. Gathering data is a vital part of the analysis, and it consumes quite some time. Go where the action or process happens, where the value is created and observe. Talk with the people who work there and ask questions to understand the situation. Be respectful, listen to carefully, and take notes. Make sure that you do not judge or criticize. The purpose of your visit is to understand the current process and get information to determine what kind of data is needed.
Using a team approach, decide what data you will collect, when, how, who will do it, and by when. Some examples are inspection records, maintenance logs, work instructions, customer complaints, time studies, and process flow charts.
Find the root cause
Now you have all the details and, there are no guessing or loose ends. Analyze the information, look for clues that would explain the incident. Try to find trends or common circumstances every time the problem occurs. Tools like the fishbone, 5 Why, Mind Map, and Pareto Analysis facilitate this process.
Plan creation and execution
You are looking for one or two causes that, corrected, will prevent the problem from occurring. If you have more, it means that you need to keep digging to find the underlying cause.
Once you have it, generate ideas or solutions for the problem. Ask what preventive actions will stop the event from happening. Evaluate and prioritize those ideas. The recommendation should directly address the root causes identified. Use PDCA to guide you through the plan and execution process.
The four steps presented above are the general steps to complete a root cause analysis. Each of them has more details and how-to information. Follow the blog to keep learning about problem-solving, RCA, and how to use for continuous improvement.