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Sometimes variables (such as those in a IBM® SPSS® Quanvert™ database) have bases actually built into the variable. Built-in bases sometimes contain filtering, which may, for example, exclude cases in a Don't know or Not answered category. When one of these bases appears in a variable, IBM® SPSS® Data Collection Survey Reporter does not add an autobase.
Note that when you select the categories and other items in a variable that you want to include in a table, you need to explicitly specify any built-in bases if you want to include them. If you do not, Survey Reporter automatically adds an autobase to ensure that the axis has a base.
For example, the Museum Quanvert sample database has a base built into all of the categorical variables. Suppose that you create a table of remember by gender and use the Edit Table Variable dialog box to edit the two variables as follows:
• In the remember variable, delete all of the items except the Base, Dinosaurs, and Fossils categories.
• In the gender variable, delete the Base only.
In the table, the side (which is based on the remember variable) will include the Quanvert base, because it is explicitly included in the specification for the variable, whereas the top (which is based on the gender variable) will not, because it is not included in the specification. Therefore, Survey Reporter will create an autobase for the top but not for the side.
Both of the bases in the table have the default label of "Base" and so the fact that one is an autobase and the other is the built-in Quanvert base is not immediately obvious simply from looking at the table.
Note that when you create a new variable based on an existing variable that contains built-in special items, the special items are not copied to the new variable. See the topic Creating new variables for more information.