Use Committee (IACUC). All laboratory experiments involving living animals are reviewed and approved by this committee. In addition to proving the potential for benefit to human health, minimization of pain and distress, and timely and humane euthanasia, experimenters must justify their protocols based on the principles of Replacement, Reduction and Refinement. Replacement refers to efforts to engage alternatives to animal use. This includes the use of computer models, non-living tissues and cells, and replacement of "higher-order" animals (primates and mammals) with "lower" order animals (e.g. cold-blooded animals, invertebrates, bacteria) wherever possible (list of common model organisms approved for use by the NIH). Reduction refers to efforts to minimize number of animals used during the course of an experiment, as well as prevention of unnecessary replication of previous experiments. To satisfy this requirement, mathematical calculations of statistical power are employed to determine the minimum number of animals that can be used to get a statistically significant experimental result. Reduction involves methods to maximize information provided while minimizing the number of animals applied. Refinement refers to efforts to make experimental design as painless and efficient as possible in order to minimize the suffering of each animal subject. While significant advances have been made in the care and treatment of animals, this is an ever-evolving debate. Animal rights and protection groups such as the ASPCA, PETA and BUAV continue to advocate for the best laboratory conditions, and experimental protocols possible for animals in research. Pressure from these groups has also led to novel modes of experimentation, which does not involve the sacrifice of live animals. One aspect of this debate; however, continues to be difficult to resolve: the classification of animals according to a hierarchy, which protects some species more than others. Next to humans, primates are the most protected species in experimentation. The rationale for this has both evolutionary and philosophical underpinnings. Because chimpanzees and other non-human primates can demonstrate intelligence, and social structure that they have a life experiences that is more cognitively complex than lower species. Conversely, this kind of moralizing of complexity of interaction and thought could be considered "specieisism." Ultimately, this is an argument not likely to be resolved, however most people are more comfortable with the idea of experimentation that involves worms or flies than mice, dogs, or monkeys. Alternatives Ethical concerns, as well as the cost, maintenance and relative inefficiency of animal research has encouraged development