The ability to develop and test theories using data is central to the development of foundational theories in any field. In mixed martial arts, the large volume of fight data that has accumulated over the years enables us to conduct systematic testing of layman theories about mixed martial arts competition outcomes, and to develop a rigorous conceptual framework for professionals in the field. Using data from hundreds of fights, this book provides empirically tested answers to a long list of questions such as these: What are the effects of height and reach advantage on a fighter's likelihood of winning an MMA fight? Does age affect how a fighter wins? Is there a hometown advantage? Do fighters' pre-fight rituals affect the way fights end? Do southpaw fighters have an advantage over their orthodox opponents? How does a fighter's weight affect the types of injuries experienced in a fight? Are fighters from certain countries better than others? How accurately can fight outcomes be predicted? Utilizing a scientific approach, the book tests common theories about what drives success in mixed martial arts combat. "