The selection operator defines the process by which individuals are chosen from the current population to act as the “parents” of the next generation. Almost always, selection operators determine whether an individual should become a parent based on their fitness.
In EDO, a proportion of the best performing individuals are taken from a population into the next. You can also choose to include some randomly selected, or “lucky”, individuals to be carried forward with the fittest members of the population, if there are any still available.
This selection method is a variant of the classic truncation selection method with a fixed selection proportion. When lucky individuals are included, a level of noise is introduced which can increase convergence rates [Jeb13].
Taking lucky individuals should be done with caution as the associated noise can also throw the algorithm off. The use of this functionality is only encouraged for particularly complex contexts where you are unable to obtain satisfactory results otherwise.