1. A computer program product for guiding a population-based metaheuristic search for an optimization problem, the computer program product comprising: a computer readable storage device having computer usable program code embodied therewith, the computer usable program code comprising a computer usable program code to: for each candidate solution in a current iteration of a population-based metaheuristic instance, prior to evaluation of the candidate solution and generation of a figure of merit with the fitness function, determine whether the structure indicates a previously observed worst figure of merit for actual design parameters of the candidate solution that satisfied a threshold; obviate evaluation of the candidate solution and supply the previously observed worst figure of merit associated with the actual design parameters of the candidate solution in the structure when the previously observed worst figure of merit satisfies the threshold; determine whether a figure of merit generated from a fitness function of the population-based metaheuristic instance for the candidate solution is worse than a figure of merit associated with actual design parameters of the candidate solution in a structure used to track worst observed figures of merit by actual design parameters over iterations, wherein the actual design parameters are a subset of actual parameters of the candidate solution; update the structure to associate the figure of merit with the actual design parameters when the figure of merit generated for the candidate solution in the current iteration is worse than a previously observed worst figure of merit for the actual design parameters in the structure; and supply, as a figure of merit to be used for the candidate solution in advancing the population-based metaheuristic instance, the worst between the figure of merit generated for the candidate solution in the current iteration and the previously observed worst figure of merit for the actual design parameters.