Create a Pareto chart for defects by process step

Create a Pareto chart for defects by process step

Problem Statement

Create a Pareto Chart for the following data attachment collected over six months. The data shows the number of defects observed in different steps in a process. Determine how many steps we need to work on to solve at least 80% of the problem. 

How to create Pareto charts

Step 1: Open Sigma Magic
  1. Click on the Sigma Magic button on the Excel toolbar.
  2. Click on the New button to create a new project.
Step 2: Data Preparation
  1. Open the Pareto.xlsx attachment
  2. Select the data and convert it to table format by clicking Ctrl-T.


Step 3: Add the Pareto chart template to your workbook
  1. Click on the Tool Wizard to add the analysis template.
  2. Click on Graph and then Pareto Chart.


Step 4: Specify the analysis options
A new Pareto Chart worksheet will be added to your workbook, and the following dialog box will be opened. Click on the Setup tab on the right. Accept the default values and specify the analysis options.



Next, click on the Data tab and specify the data. Drag and drop the Table1 Step Name the to the Frequency Variables and Table 1 Defects to the Categorical Variables.


Click on the Charts tab if you need to change the charts. You can specify the following:  

 Labels:

  • Add a title for the chart.
  • Label the X-axis and Y-axis appropriately.

Appearance:

  • Adjust colors, font sizes, or other visual elements as needed.
  • Enable/disable gridlines or background shading.

Finally, click the Verify tab to ensure all the inputs are okay and shown in a green checkmark.



Step5: Generate analysis results
Click on the OK button to generate analysis results. The following figure shows an example output screen.



How to interpret Pareto chart analysis

The following conclusion can be drawn from this analysis.
  1. Step 4 and Step 2 account for the majority of defects.
  2. To address 80% of the defects, we need to focus on two steps:
    1. Step 4 (45 defects)
    2. Step 2 (22 defects).
  3. Total defects across all steps: 97
  4. Average defects per step: 9.7
  5. High standard deviation (13.86) indicates high variability between steps
  6. Step 4 alone contributes to 46.39% of all defects.

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