By default, Column Comparisons test all non-NET categories within a row and within a Span. This article describes how to specify which columns you want to compare, rather than doing all possible column comparisons. Any changes you make to the columns tested for a particular variable set will appear in all tables where that variable set is used in the columns.
For example, let's say I want to do a column comparison of the following table to see which percentages are significantly different from each other...
...but rather than doing all possible column comparisons, I only want to compare Columns A vs B; B vs C; and C vs D.
Familiarity with Displayr's significance testing settings. See: How to Apply Significance Testing in Displayr
A table with:
1. Compare columns selected in the Properties > APPEARANCE > Significance menu
2. A categorical question or banner with at least one categorical variable set used in the columns (cannot be a date question).
- Select a table
- If column comparisons are not already enabled, go to the object inspector on the right and select Properties > Significance > Compare Columns
By default, you get all possible paired comparisons, but we needed to take this step to get the Column Names at the bottom of the table. You will need these names to define your custom column comparisons.
- Select a column in the table. It does not matter which one you select. If using a table with spans or a banner, select the span you want to modify.
- In the Object Inspector, select Properties > Significance > Advanced > Column Comparisons. Near the bottom of the window, you'll see a new section with the name of the variable set in the columns, in this case, "Age". This is where you can change the column comparison settings of this variable set that will be used across all tables.
- At the bottom of the dialog, click Custom
Custom overrides Displayr's default choice of columns to compare and allows you to enter the specific groups of column letters to compare. This can be done for the entire table when there are no spans or Recycle column letters is unchecked in the Statistical Assumptions settings, or for an individual span if that span is selected in Step 1. The default setting includes all possible paired comparisons in the table, excluding the NET. If you enter "A/B, A/C" then only two significance tests will occur within the span: A vs B, and A vs C. B and C will not be tested against one another.
In our case, we want to compare just adjacent age groups, so we will enter "A/B, B/C, C/D". Whatever changes you make here will be applied to this variable set whenever it appears as the columns of a table that uses column comparisons.
- In the Custom box, enter "A/B, B/C, C/D"
- If you select, Apply to Selection, these comparison settings will be saved with the variable set used in the columns and will appear anywhere this variable set is used in the entire document. If you select Set as Default, these settings will be the default for all tables in your document if those tables' settings haven't been modified from the default. To learn more about defaults, see: How to Set the Default Type of Significance Test.
The results are as follows:
- Optional: To see which columns are being compared in the table, select Columns Compared in the Inputs > STATISTICS >Below menu in the object inspector on the right.