Root Cause Analysis Explained: Definition, Examples, and Methods

The easiest way to understand root cause analysis is to think about common problems. If we’re sick and throwing up at work, we’ll go to a doctor and ask them to find the root cause of our sickness. If our car stops working, we’ll ask a mechanic to find the root cause of the problem. If our business is underperforming (or overperforming) in a certain area, we’ll try to find out why. For each of these examples, we could just find a simple remedy for each symptom. To stop throwing up at work, we might stay home with a bucket. To get around without a car, we might take the bus and leave our broken car at home. But these solutions only consider the symptoms and do not consider the underlying causes of those symptoms—causes like a stomach infection that requires medicine or a busted car alternator that needs to be repaired. To solve or analyze a problem, we’ll need to perform a root cause analysis and find out exactly what the cause is and how to fix it.

In this article, we’ll cover the following:

  1. Definition of root cause analysis
  2. Benefits and goals of root cause analysis
  3. How to conduct root cause analysis
  4. Tips for performing rot cause analysis

What is root cause analysis?

This Tableau Workbook demonstrates a root cause analysis dashboard.

Root cause analysis (RCA) is the process of discovering the root causes of problems in order to identify appropriate solutions. RCA assumes that it is much more effective to systematically prevent and solve for underlying issues rather than just treating ad hoc symptoms and putting out fires. Root cause analysis can be performed with a collection of principles, techniques, and methodologies that can all be leveraged to identify the root causes of an event or trend. Looking beyond superficial cause and effect, RCA can show where processes or systems failed or caused an issue in the first place.

Core principles

There are a few core principles that guide effective root cause analysis, some of which should already be apparent. Not only will these help the analysis quality, these will also help the analyst gain trust and buy-in from stakeholders, clients, or patients.

  • Focus on correcting and remedying root causes rather than just symptoms.
  • Don’t ignore the importance of treating symptoms for short term relief.
  • Realize there can be, and often are, multiple root causes.
  • Focus on HOW and WHY something happened, not WHO was responsible.
  • Be methodical and find concrete cause-effect evidence to back up root cause claims.
  • Provide enough information to inform a corrective course of action.
  • Consider how a root cause can be prevented (or replicated) in the future.

As the above principles illustrate: when we analyze deep issues and causes, it’s important to take a comprehensive and holistic approach. In addition to discovering the root cause, we should strive to provide context and information that will result in an action or a decision. Remember: good analysis is actionable analysis.

Benefits and goals of root cause analysis

The first goal of root cause analysis is to discover the root cause of a problem or event. The second goal is to fully understand how to fix, compensate, or learn from any underlying issues within the root cause. The third goal is to apply what we learn from this analysis to systematically prevent future issues or to repeat successes. Analysis is only as good as what we do with that analysis, so the third goal of RCA is important. We can use RCA to also modify core process and system issues in a way that prevents future problems. Instead of just treating the symptoms of a football player’s concussion, for example, root cause analysis might suggest wearing a helmet to reduce the risk of future concussions. Treating the individual symptoms may feel productive. Solving a large number of problems looks like something is getting done. But if we don’t actually diagnose the real root cause of a problem we’ll likely have the same exact problem over and over. Instead of a news editor just fixing every single omitted Oxford comma, she will prevent further issues by training her writers to use commas properly in all future assignments.

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How to conduct an effective root cause analysis: techniques and methods

This Tableau workbook demonstrates a root cause analysis and the importance of asking the "why" behind your data.

There are a large number of techniques and strategies that we can use for root cause analysis, and this is by no means an exhaustive list. Below we’ll cover some of the most common and most widely useful techniques.

5 Whys

One of the more common techniques in performing a root cause analysis is the 5 Whys approach. We may also think of this as the annoying toddler approach. For every answer to a WHY question, follow it up with an additional, deeper “Ok, but WHY?” question. Children are surprisingly effective at root cause analysis. Common wisdom suggests that about five WHY questions can lead us to most root causes—but we could need as few as two or as many as 50 WHYs. Example: Let’s think back to our football concussion example. First, our player will present a problem: Why do I have such a bad headache? This is our first WHY. First answer: Because I can’t see straight. Second why: Why can’t you see straight? Second answer: Because I my head hit the ground. Third why: Why did your head hit the ground? Third answer: I got hit tackled to the ground and hit my head hard. Fourth why: Why did hitting the ground hurt so much? Fourth answer: Because I wasn’t wearing a helmet. Fifth why: Why weren’t you wearing a helmet? Fifth answer: Because we didn’t have enough helmets in our locker room. Aha. After these five questions, we discover that the root cause of the concussion was most likely from a lack of available helmets. In the future, we could reduce the risk of this type of concussion by making sure every football player has a helmet. (Of course, helmets don’t make us immune to concussions. Be safe!) The 5 Whys serve as a way to avoid assumptions. By finding detailed responses to incremental questions, answers become clearer and more concise each time. Ideally, the last WHY will lead to a process that failed, one which can then be fixed.

Change Analysis/Event Analysis

Another useful method of exploring root cause analysis is to carefully analyze the changes leading up to an event. This method is especially handy when there are a large number of potential causes. Instead of looking at the specific day or hour that something went wrong, we look at a longer period of time and gain a historical context. 1. First, we’d list out every potential cause leading up to an event. These should be any time a change occurred for better or worse or benign. Example: Let’s say the event we’re going to analyze is an uncharacteristically successful day of sales in New York City, and we wanted to know why it was so great so we can try to replicate it. First, we’d list out every touch point with each of the major customers, every event, every possibly relevant change. 2. Second, we’d categorize each change or event by how much influence we had over it. We can categorize as Internal/External, Owned/Unowned, or something similar. Example: In our great Sales day example, we’d start to sort out things like “Sales representative presented new slide deck on social impact” (Internal) and other events like “Last day of the quarter” (External) or “First day of Spring” (External). 3. Third, we’d go event by event and decide whether or not that event was an unrelated factor, a correlated factor, a contributing factor, or a likely root cause. This is where the bulk of the analysis happens and this is where other techniques like the 5 Whys can be used. Example: Within our analysis we discover that our fancy new Sales slide deck was actually an unrelated factor but the fact it was the end of the quarter was definitely a contributing factor. However, one factor was identified as the most likely root cause: the Sales Lead for the area moved to a new apartment with a shorter commute, meaning that she started showing up to meetings with clients 10 minutes earlier during the last week of the quarter. 4. Fourth, we look to see how we can replicate or remedy the root cause. Example: While not everyone can move to a new apartment, our organization decides that if Sales reps show up an extra 10 minutes earlier to client meetings in the final week of a quarter, they may be able to replicate this root cause success.

Cause and effect Fishbone diagram

Another common technique is creating a Fishbone diagram, also called an Ishikawa diagram, to visually map cause and effect. This can help identify possible causes for a problem by encouraging us to follow categorical branched paths to potential causes until we end up at the right one. It’s similar to the 5 Whys but much more visual. Typically we start with the problem in the middle of the diagram (the spine of the fish skeleton), then brainstorm several categories of causes, which are then placed in off-shooting branches from the main line (the rib bones of the fish skeleton). Categories are very broad and might include things like “People” or “Environment.” After grouping the categories, we break those down into the smaller parts. For example, under “People” we might consider potential root cause factors like “leadership,” “staffing,” or “training.” As we dig deeper into potential causes and sub-causes, questioning each branch, we get closer to the sources of the issue. We can use this method eliminate unrelated categories and identify correlated factors and likely root causes. For the sake of simplicity, carefully consider the categories before creating a diagram. Common categories to consider in a Fishbone diagram:

  • Machine (equipment, technology)
  • Method (process)
  • Material (includes raw material, consumables, and information)
  • Man/mind power (physical or knowledge work)
  • Measurement (inspection)
  • Mission (purpose, expectation)
  • Management / money power (leadership)
  • Maintenance
  • Product (or service)
  • Price
  • Promotion (marketing)
  • Process (systems)
  • People (personnel)
  • Physical evidence
  • Performance
  • Surroundings (place, environment)
  • Suppliers
  • Skills

Tips for performing effective root cause analysis

Ask questions to clarify information and bring us closer to answers. The more we can drill down and interrogate every potential cause, the more likely we are to find a root cause. Once we believe we have identified the root cause of the problem (and not just another symptom), we can ask even more questions: Why are we certain this is the root cause instead of that? How can we fix this root cause to prevent the issue from happening again? Use simple questions like “why?” “how?” and “so what does that mean here?” to carve a path towards understanding.

Work with a team and get fresh eyes

Whether it’s just a partner or a whole team of colleagues, any extra eyes will help us figure out solutions faster and also serve as a check against bias. Getting input from others will also offer additional points of view, helping us to challenge our assumptions.

Plan for future root cause analysis

As we perform a root cause analysis, it’s important to be aware of the process itself. Take notes. Ask questions about the analysis process itself. Find out if a certain technique or method works best for your specific business needs and environments.

Remember to perform root cause analysis for successes too

Root cause analysis is a great tool for figuring out where something went wrong. We typically use RCA as a way to diagnose problems but it can be equally as effective to find the root cause of a success. If we find the cause of a success or overachievement or early deadline, it’s rarely a bad idea to find out the root cause of why things are going well. This kind of analysis can help prioritize and preemptively protect key factors and we might be able to translate success in one area of business to success in another area.