“Root cause analysis (RCA) is a method of problem solving used for identifying the root causes of faults or problems. A factor is considered a root cause if removal thereof from the problem-fault-sequence prevents the final undesirable event from recurring; whereas a causal factor is one that affects an event's outcome, but is not a root cause.”
Root Cause Analysis
RCA began in the 1950s as a formal study by the National Aeronautics and Space Administration (NASA) in the United States. These included work practice, procedures, management, fatigue, time pressure, along with several others. Root Cause Analysis (RCA) helps people answer the question of why the problem occurred in the first place. It seeks to identify the origin of a problem using a specific set of steps, with associated tools, to find the primary cause of the problem, so that you can:
Determine what happened.
Determine why it happened.
Figure out what to do to reduce the likelihood that it will happen again.
RCA assumes that systems and events are interrelated. An action in one area triggers an action in another and another, and so on. By tracing back these actions, you can discover where the problem started and how it grew into the symptom you're now facing.
You'll usually find three basic types of root causes:
Physical causes – Tangible, material items failed in some way (for example, a car's brakes stopped working).
Human causes – People did something wrong, or did not do something that was needed. Human causes typically lead to physical causes (for example, no one filled the brake fluid, which led to the brakes failing).
Organizational causes – A system, process, or policy that people use to make decisions or do their work is faulty (for example, no one person was responsible for vehicle maintenance, and everyone assumed someone else had filled the brake fluid).
RCA looks at all three types of causes. It involves investigating the patterns of negative effects, finding hidden flaws in the system, and discovering specific actions that contributed to the problem. This often means that RCA reveals more than one root cause.
You can apply RCA to almost any situation. When you are utilizing the Quality Assurance Process Improvement (QAPI) process, RCA can be an excellent tool in your investigations. Determining how far to go in your investigation requires good judgment and common sense. Theoretically, you could continue to trace root causes back to the Stone Age, but the effort would serve no useful purpose. Be careful to understand when you've found a significant cause that can, in fact, be changed.
The root cause analysis process has five identifiable steps:
Step One: Define the Problem
What do you see happening?
What are the specific symptoms?
Step Two: Collect Data
What proof do you have that the problem exists?
How long has the problem existed?
What is the impact of the problem?
Step Three: Identify Possible Causal Factors
What sequence of events leads to the problem?
What conditions allow the problem to occur?
What other problems surround the occurrence of the central problem?
Use these tools to help identify causal factors:
Appreciation– Use the facts and ask "So what?" to determine all the possible consequences of a fact.
5 Whys– Ask "Why?" until you get to the root of the problem.
Drill Down– Break down a problem into small, detailed parts to better understand the big picture.
Use the same tools you used to identify the causal factors (in Step Three) to look at the roots of each factor. These tools are designed to encourage you to dig deeper at each level of cause and effect.
Step Five: Recommend and Implement Solutions
What can you do to prevent the problem from happening again?
How will the solution be implemented?
Who will be responsible for it?
What are the risks of implementing the solution?
Analyze your cause-and-effect process, and identify the changes needed for various systems. It's also important that you plan ahead to predict the effects of your solution. This way, you can spot potential failures before they happen.