Root Cause Analysis

What is Root Cause Analysis?

Root Cause Analysis (RCA) is a method used to find the root cause of any malfunction, deficiency, or problem. It is most famously used in industries such as healthcare, science, and manufacturing/engineering but its principles can be used in any environment.

As a fundamental problem-solving tool, Root Cause Analysis focuses on finding the source of the problem in order to enact effective and long-lasting solutions. Take for example someone complaining of a sore ankle. You could simply give the person some pain medication but that does not solve the root cause of the pain, only the symptom of pain.

With Root Cause Analysis, you’ll be able to discover and define what happened, why it happened, and how to prevent it from happening again.

Key Takeaways

  • Root Cause Analysis is used to determine the root cause of problems within a variety of industries and fields.

  • The 4 steps of Root Cause Analysis are identification, data collection, causal graphing, and solution.

  • Always make sure to differentiate between correlational factors and contributing factors.

  • Use tools like the 5 Whys or the Fishbone Diagram to map out causal factors.

The 3 Categories of Causal Factors

Within manufacturing or any company environment, all causal factors can be broken up into 3 broad categories.

  • Physical causes: Defective machinery, broken tools, deteriorating infrastructure, etc.
  • Human causes: Human error, improper adherence to procedures, etc.
  • Organizational causes: Unclear processes, insufficient training/onboarding, inadequate management, etc.

Most problems or malfunctions involve multiple causal factors. For example, there may be an issue with a machine (physical cause), which is due to a lack of maintenance, (human cause), which is due to the lack of a maintenance schedule being established (organizational cause).

Breaking this up into even smaller categories will provide even greater insight into the root causes of a problem. But these 3 broad categories are a great place to start.

The 4 Steps of Root Cause Analysis

Root Cause Analysis can be performed in a myriad of different ways but more often than not, the process follows these 4 core steps.

  • Identification: In this step, you’ll want to identify what the issue is, what the symptoms are, and what is observably happening. By establishing this identification, you’ll be better able to direct the rest of the analysis.
  • Data Collection: Collect all available data and fully assess the wider impact of the problem. Work your way backward by starting with the resulting issue and then find each catalyst that leads to that issue.
  • Causal graphing: Now is the time to sort out all the information you’ve gathered. Use either the 5 Whys or Fishbone diagrams to create a visual map or timeline of the events. This will enable you to find and share your Root Cause Analysis with others in a structured and visual format.
  • Solution: Once you and your team have determined what the root cause is, you can take the appropriate steps to rectify the issue. If possible, begin by fixing the root cause and then work your way up to the initial identified problem. Once this is done, the problem, root cause, and subsequent factors should be eliminated. If not, then you’ll need to restart the process.
Lightbulb Pro Tip

Pro Tip

When collecting data, make sure to carefully differentiate between correlational factors and contributing factors. More often than not, there will be a lot of factors that coincide with the occurrence of a problem while not necessarily contributing to the issue.

2 Root Cause Analysis Methods

The 5 Whys

The 5 Whys can be used in almost any Root Cause Analysis as it is a fairly simple process. The idea is to ask “why” five times when presented with a problem. This way you can progressively move from superficial causal factors to the ultimate root cause.

For example, imagine your company fabricates and assembles high-quality mechanical seals, similar to Chesterton. Quick side note, did you know they cut their training time in half by using VKS?

Back to the scenario. Lately, the seals have been failing inspection. Why? The operators are not assembling them correctly. Why? The operators are not 100% sure how the seals should be built. Why? Because they are new employees that lack sufficient training. Why? Because we don't have an adequate training program for our new employees. Why? Because the company is not prioritizing workforce improvement and training.

And here we have found the answer to our hypothetical problem. In this situation, the 5 Whys would be mapped like this.


Now the number of why’s is not a hard and fast rule. In reality, you’ll want to ask somewhere in the realm of 3-7 whys. If under that range, you’ve most likely not delved deep enough into the root cause. If over that range, you’ve most likely progressed too far into factors that are outside of your control such as the weather or global events.

Lightbulb Pro Tip

Pro Tip

This occurrence is easily avoided by using work instruction software to quickly and effectively train new hires while providing on-the-job guidance.

Fishbone Diagram

The fishbone diagram is used to investigate multiple factors that lead to one larger problem/failure/event. The resulting diagram displays all causal factors leading to the problem, which closely resembles the figure of a fishbone.

For instance, imagine your facility has been experiencing 7 separate and seemingly unrelated accidents in the past month. This is hurting productivity and is costing a significant amount in maintenance and downtime. You call a meeting with all your employees and go over the factors that have led to the higher rate of accidents and create a fishbone diagram. This breaks up all the accidents into a few basic categories to discern what areas within the operation need the most focus.

fishbone diagram

Here we can see that the bulk of the accidents fall under methods and manpower. Knowing this and unraveling it as a team enables you to find the right solutions and make an informed difference.

Lightbulb Pro Tip

Pro Tip

If having trouble knowing how to break up your fishbone diagram, try using the 5 Ms of manufacturing used in the above diagram. These are Manpower, Machines, Measurements, Methods, and Materials. You can add other factors like Environment or Money as long as they are useful to your Root Cause Analysis.

Root Cause Analysis vs Cost-Benefit Analysis

One thing to look out for with Root Cause Analysis is to make sure the solution does not cost more than the problem. Wanting to know if our processes and machines are working properly as this is never a bad thing. But at the end of the day, the solution should not cost more than living with the problem. The solution should always bring in a greater return on investment.

This is why Root Cause Analysis is key to a successful and well-maintained operation. It allows people to gain key insight into the causal factors within their operation to make smart decisions and find effective solutions.

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