One type of decision-making processes, which is often applied, based on the similarity of situations and developments. This study examines some approaches to addressing the similarities of situations and developments, including structural similarity and descriptive similarity. Structural similarity and descriptive similarity have been linked in many ways. One of these ways is based on theorems proven in algebraic systems and universal algebra theories. The authors point out that in order to assess two sets of descriptive similarity, it is first necessary to make descriptions of both sets, which must consist of relevant statements. The application of descriptive similarity in the process of managing the development of public transport systems in small towns in Estonia and Ukraine is considered. The authors presented the algorithm of decision-making process’ method. The approach how to apply the descriptive similarity between Estonian small towns and their public transport systems, and the small town of Ostroh from Ukraine is proposed. Some concrete examples and derived preliminary conclusions is presented.