Run charts track trends over time. Draw a run chart, your own or using the templates from your IHI module. A key in analyzing data is understanding that the outcomes cannot be random. Therefore, the change is intentional. In your own words, explain what the difference is between common-cause and special-cause variations. Now that you have learned about various measurement tools, reflect on how these tools are used in quality improvement. Which tools do you believe are most effective, and for what purpose would you use each tool?