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June 4, 2024

Find Red Flags in Your Data in ONLY 5 MINUTES with Control Charts

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Control charts are one of the best charts you can use for identifying outliers in a series of measurement. So what are they?

Control charts are used to monitor whether a process is performing consistently over time. It's basically a line graph that tracks data points collected at specific intervals, but with three key additions:

1. 𝗔𝘃𝗲𝗿𝗮𝗴𝗲 𝗹𝗶𝗻𝗲: This horizontal line represents the average performance of the process based on historical data.
2. 𝗖𝗼𝗻𝘁𝗿𝗼𝗹 𝗹𝗶𝗺𝗶𝘁𝘀: These are two additional horizontal lines, one above and one below the center line. They are typically 2-3 standard deviations from the average, but can be whatever number of standard deviations work for your situation. These limits reflect your "stable" range.
3. 𝗢𝘂𝘁𝗹𝗶𝗲𝗿 𝗶𝗱𝗲𝗻𝘁𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻: Color-coding the outlier marks helps you more easily identify the problems.

The line chart you create will help you see if measurements fall within the control limits. 

- If they do, it suggests the process is in control. 
- If they fall outside the control limits, it indicates a potential problem that needs additional analysis.

Control charts are widely used for quality control purposes (especially in manufacturing), but they can be applied to any process where you want to track performance over time. 

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