Nearest-neighbour methods are the methods of discriminant analysis are based on studying the training set subjects much similar to the subject to be classified. Classification might then be determined according to a simple majority verdict among those much similar or 'nearest' training set subjects, that is a subject would be assigned to the group to which the majority of the 'neighbours' belonged. Simple nearest neighbour techniques just consider the most similar neighbour. More common methods consider the k nearby neighbours, where k>1.