Bland-Altman Plot

Want an alternative to a Difference Plot?

This tool will help determine normality between measurements.

Bland-Altman Plot Overview

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 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:
  2. bland-altman-plot

  3. Input your "Old" (Original) and "New" (Current) data in Columns A and B:
  4. bland-altman-data-input

  5. 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:
  6. scatter-plot-bland-altman

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

    bland-altman-individual

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

    normality-plot-bland-altman

Learn More...

To create a Bland Altman using QI Macros...
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