What are the advantages and limitations of using a pareto chart for root cause analysis in DMAIC?

1 What is a pareto chart?

A pareto chart is a type of bar chart that shows the frequency or impact of different factors or categories in descending order, along with a cumulative line that represents the percentage of the total. The chart helps to visualize which factors or categories are most significant and how they relate to the overall problem. For example, a pareto chart can show the number of defects or complaints by type, the amount of time or money spent on each activity, or the frequency of errors or delays by source.

2 How to create a pareto chart?

To create a pareto chart, you should first define the problem and scope of the analysis. Then, you need to identify the factors or categories that contribute to the problem. This can be done through brainstorming, surveys, interviews, observations, or data collection methods. After collecting and organizing the data for each factor or category, you should sort it in descending order and calculate the cumulative percentage for each factor or category. Finally, you can plot the data as a bar chart and draw a line that shows the cumulative percentage on a secondary y-axis. This will help you interpret the chart and identify the vital few factors or categories that account for most of the problem.

3 How to use a pareto chart in DMAIC?

A pareto chart can be used in different phases of the DMAIC cycle, depending on the purpose and data available. For instance, in the Define phase, you can use a pareto chart to clarify the problem statement and project scope by showing the magnitude and distribution of the problem across different factors or categories. This can help you to focus on the most critical aspects and set goals and objectives for the improvement project. During the Measure phase, a pareto chart can establish baseline performance and the current state of the process by showing frequency or impact of defects, errors, waste, or variation across different factors or categories. This can help you to quantify the gap between current and desired state, as well as identify key performance indicators (KPIs) for the project. During Analyze phase, a pareto chart can identify and verify root causes of the problem by showing relationship between factors or categories and problem. This can help you apply 80/20 rule and prioritize most influential causes for further investigation and validation. In Improve phase, a pareto chart can evaluate and select best solutions for problem by showing expected or actual impact of each solution on factors or categories. This can help compare and rank alternatives and choose ones with highest potential for improvement and feasibility for implementation. Finally, in Control phase, a pareto chart can monitor and sustain improvement results by showing performance or variation of factors or categories after implementing solutions. This can help verify if problem has been reduced or eliminated, as well as if goals and objectives have been met or exceeded.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?