Comparative Analysis is one of the uniqueness of QlikView. It is a way to analyze data based on sets of multiple values (group comparison). It is not a comparison between two items such as Company A vs Company B. It is all about you, the user, creating customized groups on demand.
Learn what comparative analysis is all about and how you can set it in your application. This technical brief includes step-by-step instructions.
Here is a recording of how Comparative Analysis works.
See my blog post on this topic also.