EngineRoom

Multi-Vari Chart Tutorial

When to use this tool

A Multi-Vari Chart is a powerful visual tool used to analyze variability in a process across multiple factors. This chart helps identify patterns and sources of variation by displaying data in relation to different categories or conditions, such as time, machine, operator, or location.

Whether you're troubleshooting a problem, validating a process change, or just trying to understand what's driving fluctuations in your results, a Multi-Vari Chart provides an intuitive way to see how multiple variables interact.

How to use this tool in EngineRoom

Click to Download Data File

The Multi-Vari Chart uses categorical variables as input variables and one numeric variable as the response variable.

To use the Multi-Vari Chart, select the Measure menu > Basic Graphs... > Multi-Vari Chart. The tool opens in the workspace:

Multi Vari Chart with the title Diameter and a slide showing how to drag and drop onto the factor dropzone

Example:

A manufacturing company is investigating variability in the diameter of plastic tubing produced on different machines. They suspect that the variation could be influenced by three key factors:

Machine (Factor A) – Tubing is produced on one of three machines: Machine 1, Machine 2, and Machine 3.

Shift (Factor B) – Production runs on two shifts: Day Shift and Night Shift.

Operator (Factor C) – Each shift has different operators: Operator A and Operator B.

Data for Multi-Vari Chart showing a column for Machine, Shift, Operator and Diameter. Marchine shows Machine 1 as the value, Shift shows Day Shift and Night Shift, Operator shows Operator A and Operator B, and Diameter is a numeric value showing 9.988 to 10.162

Steps:

1. Open the Multi-Vari Chart tool onto the workspace.

Multi Vari Chart with the title Diameter and a slide showing how to drag and drop onto the factor dropzone

2. Click on the data source and drag Machine, Shift, and Operator onto the Factor drop zone.

Shows machine, shift, and operator variables attached to the study. The slide now shows a response variable and what can be dragged onto it

3. Drag Diameter onto the Response Variable drop zone.

Multi-Vari Chart slide with Diameter variable in dropzone. the Slide now shows two switch options

4. (Optional) Select "Show Means" or "Show Mean of Means" to get additional information displayed on the screen.

5. Click “Continue.”

The ouput shows points representing the first factor, and separate lines for each of the second factor, and groups for the third factor. If you add a fourth factor, then it will appear as different pages.

Output of multi-vari chart showing orange, blue and green dots as well as a y-axis from 9.9 to 10.3, and four different lines representing Day Shift and Night Shift and Operator A and Opterator B.

In this example, the Multi-Vari Chart shows that Machine 2 consistently produces larger diameters than the others, especially during the Night Shift. Operator B tends to produce slightly larger parts than Operator A across all machines and shifts. The largest variation appears to occur between machines, indicating equipment may be the dominant source of variation.

Multi-Vari Chart Video Tutorial

Coming Soon

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