# 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!

- 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:

- Input your "Old" (Original) and "New" (Current) data in Columns A and B:
- 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:

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

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

### Learn More...

- Scatter Plot available in QI Macros
- Tukey Quick Test Calculator available in QI Macros
- Youden Plot Template in QI Macros