The model developed by M. Cohen, J. March, and J. Olsen, which describes the decision-making in an organization based on event flows, has a wide range of applicability. However, despite the presence of a large number of works that develop the idea of the model or modify its algorithm, there is a fairly widespread point of view that treats the collective decision-making process described by the model as random movements of managers and problems to be solved according to the available choices (abstractions of committees and meetings). This ideal image is applied to the study of the processes of making both political and managerial decisions. This point of view is erroneous, in our opinion: the structure of the system of decision-making determines the behavior of managers and the effectiveness of the whole system in the most significant way. Thus, in the presence of a significant number of works that deepen the analysis of the original model (including those published in the last decade), we can state the absence of a scientific tool that allows us to visually reproduce the results of the processes of decision-making taking place in the systems of decision-making with different structures. The need to develop such a tool determines the novelty of this work. The purpose of the study is to develop a simulation model that reproduces the logic of the original model and allows to present the results of the work of the decision-making system visually. The initial data of the study were the logic and algorithm of the original model, our development tool is the NetLogo simulation environment. The developed scientific tool – a simulation model of decision-making – allows us to visually present the results of the work of the decision-making system for various types of structure, determined by the combination of the type of access structure and decision structure to the choice opportunity. The model allows us to visualize the number of solved and unsolved problems, the state of the choice possibilities at the time of the simulation experiment, the types of the solutions developed by the system, the amount of energy required to solve the problems that entered the system, and the amount of effective energy of managers that was not used in the decision-making process. The model code is available for download and modification. It can be used both in the educational process and in the study of decision-making processes in various types of organizational structures. © 2021, Springer Nature Switzerland AG.