Business Definition: A milestone in an IT project that requires that predefined criteria be met before the project can proceed to the next phase. Technical Definition: A special milestone in a software project. QGs are located between environments and tests, where the entrance criteria for the next environment is based upon the exit criteria for the activities of the previous environment and is strongly dependent on the outcome of a previous phase. They are especially useful between phases in which enhanced measurements and disciplines must be overcome. To pass through a quality gate, all demands must be met for the next phase or environment to be successful.