The present invention relates to systems and methods for improving a sort plan. According to one embodiment, several groups are formed where each group contains articles having an identifier of a hierarchical structure. In certain embodiments, the identifier may include a geographical indication, such as a postal or ZIP code. Further aspects relate to systems and methods for conducting sort plan optimization where at least some prior data is known or otherwise obtainable. In one embodiment, data relating to the quantity of groups within the sort plan, the quantity of articles associated with each identifier, and / or the quantity of articles within each group may be estimated or known. In certain embodiments, such data may be utilized to assign articles to specific bins, including any available bin, and then optimize the sort plan by selecting at least one bin for improvement.