Atrial fibrillation, a rhythm classically described as totally disorganized, is now recognized to have some structure in its activation. Even though that structure may be very complex, it clearly exists, and researchers continue to try to quantify that structure. One problem with this quantification is that "organization" is an ambiguous term that can have many interpretations. Rather than attempt to impose a particular definition of "organization," this review categorizes the methodologies for quantifying atrial fibrillation organization based on the number of recording channels used in the methods. This method of categorization is not only convenient, but is also descriptive of the different "philosophical" definitions of organization that various researchers have.