How to Specify Columns to be Compared in a Table

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 question will appear in all tables where that question 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.

Requirements

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).

Method

Right-click the table and select Table Options > Statistical Assumptions > Significance Levels
From the Show Significance menu, select Compare columns
Click OK.
By default, you get all possible paired comparisons. In our case, we want instead to compare adjacent age groups.

By default, you get all possible paired comparisons. In our case, we want instead to compare adjacent age groups.
Right-click a column head in the table (it does not matter which one)
Select Table Options > Statistical Assumptions > Column Comparisons. If you are using a table with spans or a banner, select the span you want to modify.

Near the bottom of the window, you'll see a new section with the name of the question or span in the columns of the table, in this case "Age". This is where you can change the column comparison settings of this question that will be used across all tables.

The results are as follows:
At the bottom of the dialog, click Custom and in the box type A/B,B/C,C/D.

Custom overrides Q's default choice of columns to compare and allows to you 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. 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 adjacent age groups, so we will enter "A/B, B/C, C/D". Whatever changes you make here will be applied to this question whenever it appears as the columns of a table that uses column comparisons.
Click OK

The results are as follows: