The final front accepted by a non-dominated sorting genetic algorithm might, and often will, contain more individuals than can be added to the surviving evolutionary population without exceeding its size limit. This set of individuals is known in the multi-objective optimisation community as the splitting front . Because there is no difference between the individuals in the splitting front in terms of Pareto dominance, further criteria are used to select which individuals are retained and which are discarded. In the splitting front selection procedure for non-dominated sorting genetic algorithms, this criteria is typically a measure of diversity. The NSGA-II and NSGA-III algorithms both rely on a diversity criteria, but differ significantly in how they enforce this diversity, see Figure .