Question: What is the ranking system used in combat sports, including boxing and mixed martial arts, of who the better fighters are relative to their weight, by which measure the Polish mixed martial artist Joanna Jędrzejczyk is rated the number 1 female MMA fighter in the world?
Sentence (from "Joanna Jędrzejczyk"): As of May 2017, she is the consensus #1 female strawweight, and #1 pound-for-pound female MMA fighter in the world.
Relevant evidence: Yes