This metric helps evaluate the complexity of the class. The number of class methods is usually small compared to the number of instance methods. A large number of class methods may indicate many services are handled by the class instead of by individual instances. The number of new methods decreases when you move down the inheritance tree. Therefore, the deeper the class is in the class hierarchy, the lower should be the ratio of class methods to all class methods. If this is not the case, there may be design problems.