Bland-Altman Plot

Want an alternative to a Difference Plot?

This tool will help determine normality between measurements.

What is a Bland-Altman Plot ?

Bland-Altman is a method that was developed to compare two measurements of the same variable, particularly if you are trying to introduce a new measurement capability, and determine if it creates any advantages.

Create a Bland-Altman Plot in Three Easy Steps with QI Macros!

  1. First, open the Scatter chart template located under the Chart Templates drop-down menu. Once opened, you will find a Bland-Altman Plot, along with a Scatter Plot and a Normal Probability Plot:

    bland altman plot in Excel
  2. Input your "Old" (Original) and "New" (Current) data in Columns A and B:
  3. bland altman data input example

  4. Once your data is entered, it will automatically be plotted in all (3) graphs. The Scatter Diagram will show if there is correlation between your two methods:
  5. bland altman scatter plot

    The difference between your old and new data will be calculated, along with your Mean and your Upper and Lower Limits:

    bland altman plot

    You can then use Descriptive Statistics and Normality found in the Probability Plot to see if you can assume normality:

    normality plot bland altman

Learn More...

To create a Bland Altman using QI Macros...
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