Similarity measures for 2 x 2 tables

2 x 2 tables are encountered in various scientific disciplines, including biomedical, social and behavioral sciences, economics and ecology. In the literature many different similarity measures have been proposed that can be used to further summarize the information in a 2 x 2 table. Many of these measures are just functions of the four cells. In this paper the important ones are reviewed. Furthermore, it is shown how various similarity measures are related to one another by considering certain general similarity measures that have various important similarity measures as special cases. The presented overview may provide insights that may be helpful to researchers from various scientific disciplines in deciding what similarity measure to use in applications or for studying theoretical properties.