Using mice from different breeders fails to improve replicability of results

Abstract Theoretical and empirical evidence indicates that low external validity due to rigorous standardization of study populations is a cause of poor replicability in animal research. Here, we report a multi-laboratory study to test whether heterogenization of study populations by using animals from different breeders increases the replicability of results from single-laboratory studies. We found that heterogenization by breeder was not potent enough to increase external validity sufficiently to improve replicability.