Treatment coefficient, or TC, was a number assigned to a person on, or visiting, Dinaal. Following the Jyes' intervention in the mid-24th century, the Dinaali medical system was based on the "TC" and the Allocator. The amount of medical treatment and medication a person received depended on how high a person's TC was. The TC was, supposedly, a complex formula of a person's education and general usefulness for society. (VOY: "Critical Care")