IT organizations looking to improve their testing practices often opt to centralize some or all test-related activities in a testing center of excellence (COE). There are four primary models for a test COE, each with a different role and set of responsibilities. Because testing is a mission-critical activity, smart IT organizations proceed cautiously in their establishment of a test COE, often layering one model on top of another. A large insurance company built its high-performing test COE in this fashion, starting small and building it out over the course of three years.