A priori segmentation refers to a segmentation technique based on conventional assumptions rather than on market research. Marketers group consumers according to predefined criteria such as demographics, behavior, psychographics, and lifestyle. For example, they first choose segmentation variables, such as age or income; and classify customers according to those variables.
This technique is contrasted to the post hoc segmentation, where, after existing consumers data is analyzed, segments are then chosen based on similarities and differences formed.