Root cause analysis (RCA)

Abstract

While managing programs or projects we face many challenges which affect the schedule or quality of the project. For the elimination of such similar future challenges, it is important to identify from where the problem has started (Root Cause). Root cause analysis is a method to identify the source of the problem and to know how it has happened and how to prevent such problems in future. Multiple industries like Construction, manufacturing, pharmaceutical, Information technology uses this method for successful identification of causes for the problem. RCA also gives the scope to identify the gaps in the existing process, reduce the cost of production or increase production. In this article, we will learn about What is root cause analysis and its importance, when and how RCA has to be done and methods of doing root cause analysis.

Introduction

Root cause illustration

Root cause analysis (RCA) is an important aspect of a broad problem-solving process and continuous improvement. A root cause is a part that contributed to a failure and should be removed completely using process improvement. The root cause is the most fundamental problem—the most fundamental reason—that puts in motion the a whole cause-and-effect that leads to the problem. Root cause analysis alone would not give any results, it has to be used as part of a bigger problem-solving effort aimed at improving quality. Organization uses continuous improvement method to remove that problem completely .

Root cause analysis refers to a variety of methodologies, tools, and procedures used to identify the root causes of issues. Some RCA approaches are more focused toward finding actual root causes than others, while others are more broad problem-solving procedures, but others simply provide support for the root cause analysis core activity.[1]

Root cause analysis tools

Five Why analysis

Five Why analysis is widely used root cause analysis tool in the industry as it helps to identify the root cause with few simple “WHY” question and without in need of any statistical tool. This method is one of the fasted methods to know the real root cause of the problem. In 1930s this tool was developed by Sakichi Toyoda, Founder of Toyota Industries, but only in 1970s this tool was used in many industries. [2]

Steps to perform five why analysis

1. Take a particular problem
2. Question “WHY” it occurred and note down the answer.
3. If that is not the exact root cause then you can ask another “WHY” question to that answer .Note down the new answer.
4. Follow these steps till you identify the root cause. It can take any number of “WHY” to reach the cause. [3]

Example

Problem: Car Tire got punctured

Root Cause: There was a hole on the roof.

Remedy: To avoid car tire puncture like this we need to fix the hole on the roof

Fishbone diagram

Fishbone diagram was developed by Kaoru Ishikawa. So, it is also called as “Ishikawa diagram”. This method is done through a diagram which looks like a fishbone. The diagram shows the primary and sub cause for that result. Usually, the diagram is made through team brainstorming. In this the effect or the problem will be in the place of fish head and the primary and sub cause will be there in bone of the fish. [4]

This method is commonly used in various manufacturing and operations industry . Instead of focusing on a single cause, this approach provides us with a comprehensive list of all probable causes, which aids not only in discovering the core cause of the current problem but also in preventing future mishaps.

Steps to analysis fishbone diagram

1. Determine and state the effect or the problem that has to be analyzed.
2. Determine the primary causes or categories of the effect.Methods, machines, people, materials, environment or measurements are popular primary causes.
3. Under each primary categories identify the other sub causes on it. Sub causes can be identified through various methods like five why analysis or 4Ps method (Policies, Procedures, People and Plant) 
4. This procedure of analyzing each cause is repeated until the problem's root causes are found. The team then analyzes the fishbone diagram until a conclusion and future steps are reached.[5]

Example

Scatter chart

Scatter chart represents the relationship between dependent and independent variables for the root cause. The dependent and independent variables data is represented by numerical value. [7]

Steps to create a scatter plot

1. Choose two variables to analyze (Pair of dependent and independent variables).
2. Measure the equivalent value of the dependent variable for each value of the independent variable.
3. On the chart, plot the numbers from each data pair.
4. On the horizontal axis, place the independent or expected cause variable, and on the vertical axis, place the dependent or intended effect variable.
5. In the chart, plot and examine the acquired data values. [7]

Example

Gantt charts

In today’s industry nearly 95% of the projects uses Gannt charts for their projects as it is one of the best indication tool. Gantt chart helps to keep a track on the progress of the project. Gantt chart helps to keep a track on the progress of the project. [7]

Steps to create a Gantt chart

1. Make a list of all tasks and activities.
2. Calculate the latest finishing date and the earliest start date for each activity, as well as the duration and any interdependence on other activities.
3. Arrange the tasks in a blank Gantt chart, with the timeline indicating the project's overall duration.
4. Draw bars that match to the duration of the activities to schedule them.
5. Use diamonds to represent plan milestones. [7]

Example

Flowcharts

Flowchart represent the process flow which was used through a simplified representation. [7]

Steps to create flowcharts

1. Gather all of the team members in the process in a meeting room with a whiteboard and plenty of colorful sticky note
2. Define the process's beginning and end points, as well as the borderline between other parallel processes.
3. List the primary actions or tasks that were completed during the procedure 
4. Use different colored adhesive notes to represent actions, items, documents, and other process elements.
5. Draw a diagram of the process by shifting the notes about on the board until they reflect the most accurate representation of the process. [7]

Symbols

Pareto analysis

Pareto principle was formed after Vilredo Pareto, an Italian economist, he designed a principle to represent 80% of wealth in the country is owned by 20% of the people. Pareto analysis is a helpful tool when there are several influencing factors for the results. Pareto analysis helps to develop and organize ideas. This tool primary assists the user to figure out top 20% of the root cause which can affect 80% end result. So, it is also called as 80/20 rule. [8]

Pareto analysis can also be helpful and give deeper understanding of the problems that must be addressed on priority. A Pareto chart may also be used to estimate the cumulative effect of a problem. To put it in another way, cumulative impact is the result of a fault occurring over a considerable amount of time. It also supports in handling multiple organizational challenges. [9]

Steps to perform pareto analysis

1. Collect the number defect occurrence.
2. Sort that data from highest to lowest based on the number of occurrences.
3. Calculate the cumulative percentage.
4. Plot a bar graph where X-axis is the defect causes and Y-axis is the cumulative percentage.
5. Plot another line graph in that bar graph for the cumulative percentage.
6. To separate the important root cause draw a line from Y-Axis at 80% to the line graph and then drop to the X-Axis. The causes that are left side to the line are the 80% defect driving factors. [8]

Example

Histogram

Histogram is popularly known as bar chart and it is used to show the distribution and variation of the data. The advantage of the histogram is that it presents data in a manner that makes it simple to see relationships, making it more suitable at practically any level of the RCA process. A histogram can be used in root cause analysis to Illustrate the frequency of event occurrences, its causes, and outcomes and Find out the impact of implemented solutions. [7]

Steps to create a histogram

1. Split the obtained data into an appropriate number of categories if it hasn't already been done.
2. Make a bar chart with area for the number of data categories on the X axis and the maximum data point on the vertical axis.
3. For each data point, make a bar with a height that matches to the recorded data.
4. Look for trends in the histogram results. Reevaluate the number of categories and the data division into the categories if your result with a graph with very few bars, all bars almost equal, or a comb-like design. [7]

Example

Brainstorming

The goal of brainstorming is to generate as much thoughts as possible which are probable factors for the event under study, even wild ideas. [7]

Steps to do brainstorming session

1. Get a whiteboard or a flip chart to write down your ideas. 2. Encourage everyone to engage by opening the stage to attendees for the intent of launching ideas. 3. Make a list of all the ideas you've come up with, using the same language as the original proposal. 4. During the session, don't really debate, criticize, or evaluate ideas. 5. Allow for a period of stagnation in the flow of thoughts because it will generally take up again; end the session when very few fresh ideas come. 6. Sort ideas into categories of decreasing importance to review them. [7]

Impact effort matrix

It's a method for determining which of many possible solutions should be executed. It shows which ideas look to be the simplest to implement and which have the greatest impact. [7]

Steps to create the Impact effort matrix

1. Lookup past discussions' possible solutions. 2. Create a blank diagram, dividing it into four quadrants, with the effort necessary to implement the solution on the x axis and the impact of the approach on the y axis. 3. Evaluate effort and impact, and then position each option in the graph based on your findings. To identify each reason, use figures, shades, or titles. 4. The options in the upper left quadrant will provide the best value and should be prioritized. [7]

Example