The principle of limiting or reducing the severity of scientific procedures by treating laboratory animals in such a way that potential pain, distress and other deleterious effects inflicted on the animals are avoided, alleviated, or minimized.  It may also be a way in which their welfare can be improved e.g. through enrichment of their husbandry. In laboratory animal care, Refinement is known as one of the 3 Rs in the Three Rs ethical framework.