Determine the source of variation in multi-vari chart?

In a multi-vari chart, the source of variation is typically attributed to different factors or variables that can influence the process being studied. These factors can include individual elements such as machines, operators, materials, and environmental conditions. By analyzing the chart, one can identify which sources contribute most significantly to the variation and understand how they interact with each other. This helps in pinpointing areas for improvement and optimizing the overall process.