1. Statistical Reference Guide
  2. Method comparison / Agreement

Plotting the Bland-Altman limits of agreementPlot a difference plot and limits of agreement.

  1. Select a cell in the dataset.
  2. On the Analyse-it ribbon tab, in the Statistical Analyses group, click Method Comparison(or Agreement depending on the edition), and then click Bland-Altman.
    The analysis task pane opens.
  3. If the data are in 2 variables:
    1. In the X drop-down list, select the comparative or reference measurement procedure variable.
    2. In the Y drop-down list, select the test measurement procedure variable.
    Note: If the variables consist of replicate measurements, select the variable name that spans all the replicate columns.
  4. If the data are in 2 variables with a separate variable identifying replicates of each item:
    1. In the X drop-down list, select the comparative or reference measurement procedure variable.
    2. In the Y drop-down list, select the test measurement procedure variable.
    3. In the Item drop-down list, select the variable identifying each item.
  5. If the data are in a single variable with a separate variable matching each item and a variable identifying the method:
    1. In the Model drop-down menu, select Matched Pairs.
    2. In the Y drop-down list, select the measurement variable.
    3. In the Item drop-down list, select the item variable that identifies each item.
    4. In the Method drop-down list, select the method variable.
  6. In the D drop-down list, select:
    Option Description
    Difference Plot the differences on the vertical axis.
    Relative Difference Plot the differences relative to Z on the vertical axis.
    Ratio Plot the ratio of the values on the vertical axis.
  7. In the on Z drop-down list, select:
    Option Description
    X Plot X as a reference method on the horizontal axis.
    (X+Y)/2 Plot the average on the horizontal axis. Neither X or Y are reference methods.
  8. In the Mean function drop-down list, select:
    Option Description
    Constant There is a constant relationship between D and Z.
    Linear function There is a linear relationship between D and Z.
  9. In the SD drop-down list, select:
    Option Description
    Constant The measurement error is constant throughout the measuring interval.
    Linear function The measurement error is linear across the measuring interval.
  10. Click Calculate.
Available in
Method Validation Edition Medical Edition Ultimate Edition

From the Statistical Reference Guide for Analyse-it 6.24.0: https://analyse-it.com/docs/user-guide/method-comparison/plotting-bland-altman-plot

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