Endometriosis is classified into four stages by the American Society for Reproductive Medicine: I (minimal), II (mild), III (moderate), and IV (severe). Criteria for determining those stages are based on the location of the endometriosis, the extent to which it has spread, the depth of the endometriosis, the presence and size of ovarian endometriomas (more on those in just a moment), and the presence and severity of adhesions. A point system determines the stage a woman is in. It has been revised three times in the past forty or so years to reflect the continued progress we have made in learning about the disease. A score of one to fifteen indicates minimal or mild endometriosis (stage I or II). A score of sixteen or higher indicates moderate to severe endometriosis (stage III or IV). However, the point system and the four stages have no specific correlation to any symptoms and exclude the infiltrative nature of the disease. That means the level of pain a woman is in plays no role in determining which stage she is in. So someone with stage IV (severe) endometriosis may feel little or nothing at all, while someone with a stage I (mild) case could be seriously hurting.