This article is part of The Definitive Guide to Uploading and Preparing Data.
An interaction is when you cross several categorical variables to expand the number of categories. This is the similar concept of 'nesting' where you 'nest' one variable within another, leading to a multiplicity of categories. This can be useful to create variables to be used as multitable/crosstab banners.
For example, if you have a Gender variable (2 categories) and an Age variable (3 categories), when you create an interaction between them, you will end up with 6 categories in the new variable (e.g., Males 18-34, Males 35-49).
New Interaction Variable